libcurl extracted to the separate lib

git-svn-id: http://svn.miranda-ng.org/main/trunk@14683 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c

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+LATEST VERSION
+
+  You always find news about what's going on as well as the latest versions
+  from the curl web pages, located at:
+
+        http://curl.haxx.se
+
+SIMPLE USAGE
+
+  Get the main page from Netscape's web-server:
+
+        curl http://www.netscape.com/
+
+  Get the README file the user's home directory at funet's ftp-server:
+
+        curl ftp://ftp.funet.fi/README
+
+  Get a web page from a server using port 8000:
+
+        curl http://www.weirdserver.com:8000/
+
+  Get a directory listing of an FTP site:
+
+        curl ftp://cool.haxx.se/
+
+  Get the definition of curl from a dictionary:
+
+        curl dict://dict.org/m:curl
+
+  Fetch two documents at once:
+
+        curl ftp://cool.haxx.se/ http://www.weirdserver.com:8000/
+
+  Get a file off an FTPS server:
+
+        curl ftps://files.are.secure.com/secrets.txt
+
+  or use the more appropriate FTPS way to get the same file:
+
+        curl --ftp-ssl ftp://files.are.secure.com/secrets.txt
+
+  Get a file from an SSH server using SFTP:
+
+        curl -u username sftp://shell.example.com/etc/issue
+
+  Get a file from an SSH server using SCP using a private key to authenticate:
+
+        curl -u username: --key ~/.ssh/id_dsa --pubkey ~/.ssh/id_dsa.pub \
+            scp://shell.example.com/~/personal.txt
+
+  Get the main page from an IPv6 web server:
+
+        curl -g "http://[2001:1890:1112:1::20]/"
+
+DOWNLOAD TO A FILE
+
+  Get a web page and store in a local file with a specific name:
+
+        curl -o thatpage.html http://www.netscape.com/
+
+  Get a web page and store in a local file, make the local file get the name
+  of the remote document (if no file name part is specified in the URL, this
+  will fail):
+
+        curl -O http://www.netscape.com/index.html
+
+  Fetch two files and store them with their remote names:
+
+        curl -O www.haxx.se/index.html -O curl.haxx.se/download.html
+
+USING PASSWORDS
+
+ FTP
+
+   To ftp files using name+passwd, include them in the URL like:
+
+        curl ftp://name:passwd@machine.domain:port/full/path/to/file
+
+   or specify them with the -u flag like
+
+        curl -u name:passwd ftp://machine.domain:port/full/path/to/file
+
+ FTPS
+
+   It is just like for FTP, but you may also want to specify and use
+   SSL-specific options for certificates etc.
+
+   Note that using FTPS:// as prefix is the "implicit" way as described in the
+   standards while the recommended "explicit" way is done by using FTP:// and
+   the --ftp-ssl option.
+
+ SFTP / SCP
+
+   This is similar to FTP, but you can specify a private key to use instead of
+   a password. Note that the private key may itself be protected by a password
+   that is unrelated to the login password of the remote system.  If you
+   provide a private key file you must also provide a public key file.
+
+ HTTP
+
+   Curl also supports user and password in HTTP URLs, thus you can pick a file
+   like:
+
+        curl http://name:passwd@machine.domain/full/path/to/file
+
+   or specify user and password separately like in
+
+        curl -u name:passwd http://machine.domain/full/path/to/file
+
+   HTTP offers many different methods of authentication and curl supports
+   several: Basic, Digest, NTLM and Negotiate. Without telling which method to
+   use, curl defaults to Basic. You can also ask curl to pick the most secure
+   ones out of the ones that the server accepts for the given URL, by using
+   --anyauth.
+
+   NOTE! According to the URL specification, HTTP URLs can not contain a user
+   and password, so that style will not work when using curl via a proxy, even
+   though curl allows it at other times. When using a proxy, you _must_ use
+   the -u style for user and password.
+
+ HTTPS
+
+   Probably most commonly used with private certificates, as explained below.
+
+PROXY
+
+ curl supports both HTTP and SOCKS proxy servers, with optional authentication.
+ It does not have special support for FTP proxy servers since there are no
+ standards for those, but it can still be made to work with many of them. You
+ can also use both HTTP and SOCKS proxies to transfer files to and from FTP
+ servers.
+
+ Get an ftp file using an HTTP proxy named my-proxy that uses port 888:
+
+        curl -x my-proxy:888 ftp://ftp.leachsite.com/README
+
+ Get a file from an HTTP server that requires user and password, using the
+ same proxy as above:
+
+        curl -u user:passwd -x my-proxy:888 http://www.get.this/
+
+ Some proxies require special authentication. Specify by using -U as above:
+
+        curl -U user:passwd -x my-proxy:888 http://www.get.this/
+
+ A comma-separated list of hosts and domains which do not use the proxy can
+ be specified as:
+
+        curl --noproxy localhost,get.this -x my-proxy:888 http://www.get.this/
+
+ If the proxy is specified with --proxy1.0 instead of --proxy or -x, then
+ curl will use HTTP/1.0 instead of HTTP/1.1 for any CONNECT attempts.
+
+ curl also supports SOCKS4 and SOCKS5 proxies with --socks4 and --socks5.
+
+ See also the environment variables Curl supports that offer further proxy
+ control.
+
+ Most FTP proxy servers are set up to appear as a normal FTP server from the
+ client's perspective, with special commands to select the remote FTP server.
+ curl supports the -u, -Q and --ftp-account options that can be used to
+ set up transfers through many FTP proxies. For example, a file can be
+ uploaded to a remote FTP server using a Blue Coat FTP proxy with the
+ options:
+
+   curl -u "Remote-FTP-Username@remote.ftp.server Proxy-Username:Remote-Pass" \
+    --ftp-account Proxy-Password --upload-file local-file \
+    ftp://my-ftp.proxy.server:21/remote/upload/path/
+
+ See the manual for your FTP proxy to determine the form it expects to set up
+ transfers, and curl's -v option to see exactly what curl is sending.
+
+RANGES
+
+  HTTP 1.1 introduced byte-ranges. Using this, a client can request
+  to get only one or more subparts of a specified document. Curl supports
+  this with the -r flag.
+
+  Get the first 100 bytes of a document:
+
+        curl -r 0-99 http://www.get.this/
+
+  Get the last 500 bytes of a document:
+
+        curl -r -500 http://www.get.this/
+
+  Curl also supports simple ranges for FTP files as well. Then you can only
+  specify start and stop position.
+
+  Get the first 100 bytes of a document using FTP:
+
+        curl -r 0-99 ftp://www.get.this/README
+
+UPLOADING
+
+ FTP / FTPS / SFTP / SCP
+
+  Upload all data on stdin to a specified server:
+
+        curl -T - ftp://ftp.upload.com/myfile
+
+  Upload data from a specified file, login with user and password:
+
+        curl -T uploadfile -u user:passwd ftp://ftp.upload.com/myfile
+
+  Upload a local file to the remote site, and use the local file name at the remote
+  site too:
+
+        curl -T uploadfile -u user:passwd ftp://ftp.upload.com/
+
+  Upload a local file to get appended to the remote file:
+
+        curl -T localfile -a ftp://ftp.upload.com/remotefile
+
+  Curl also supports ftp upload through a proxy, but only if the proxy is
+  configured to allow that kind of tunneling. If it does, you can run curl in
+  a fashion similar to:
+
+        curl --proxytunnel -x proxy:port -T localfile ftp.upload.com
+
+ HTTP
+
+  Upload all data on stdin to a specified HTTP site:
+
+        curl -T - http://www.upload.com/myfile
+
+  Note that the HTTP server must have been configured to accept PUT before
+  this can be done successfully.
+
+  For other ways to do HTTP data upload, see the POST section below.
+
+VERBOSE / DEBUG
+
+  If curl fails where it isn't supposed to, if the servers don't let you in,
+  if you can't understand the responses: use the -v flag to get verbose
+  fetching. Curl will output lots of info and what it sends and receives in
+  order to let the user see all client-server interaction (but it won't show
+  you the actual data).
+
+        curl -v ftp://ftp.upload.com/
+
+  To get even more details and information on what curl does, try using the
+  --trace or --trace-ascii options with a given file name to log to, like
+  this:
+
+        curl --trace trace.txt www.haxx.se
+
+
+DETAILED INFORMATION
+
+  Different protocols provide different ways of getting detailed information
+  about specific files/documents. To get curl to show detailed information
+  about a single file, you should use -I/--head option. It displays all
+  available info on a single file for HTTP and FTP. The HTTP information is a
+  lot more extensive.
+
+  For HTTP, you can get the header information (the same as -I would show)
+  shown before the data by using -i/--include. Curl understands the
+  -D/--dump-header option when getting files from both FTP and HTTP, and it
+  will then store the headers in the specified file.
+
+  Store the HTTP headers in a separate file (headers.txt in the example):
+
+        curl --dump-header headers.txt curl.haxx.se
+
+  Note that headers stored in a separate file can be very useful at a later
+  time if you want curl to use cookies sent by the server. More about that in
+  the cookies section.
+
+POST (HTTP)
+
+  It's easy to post data using curl. This is done using the -d <data>
+  option.  The post data must be urlencoded.
+
+  Post a simple "name" and "phone" guestbook.
+
+        curl -d "name=Rafael%20Sagula&phone=3320780" \
+                http://www.where.com/guest.cgi
+
+  How to post a form with curl, lesson #1:
+
+  Dig out all the <input> tags in the form that you want to fill in. (There's
+  a perl program called formfind.pl on the curl site that helps with this).
+
+  If there's a "normal" post, you use -d to post. -d takes a full "post
+  string", which is in the format
+
+        <variable1>=<data1>&<variable2>=<data2>&...
+
+  The 'variable' names are the names set with "name=" in the <input> tags, and
+  the data is the contents you want to fill in for the inputs. The data *must*
+  be properly URL encoded. That means you replace space with + and that you
+  replace weird letters with %XX where XX is the hexadecimal representation of
+  the letter's ASCII code.
+
+  Example:
+
+  (page located at http://www.formpost.com/getthis/
+
+        <form action="post.cgi" method="post">
+        <input name=user size=10>
+        <input name=pass type=password size=10>
+        <input name=id type=hidden value="blablabla">
+        <input name=ding value="submit">
+        </form>
+
+  We want to enter user 'foobar' with password '12345'.
+
+  To post to this, you enter a curl command line like:
+
+        curl -d "user=foobar&pass=12345&id=blablabla&ding=submit"  (continues)
+          http://www.formpost.com/getthis/post.cgi
+
+
+  While -d uses the application/x-www-form-urlencoded mime-type, generally
+  understood by CGI's and similar, curl also supports the more capable
+  multipart/form-data type. This latter type supports things like file upload.
+
+  -F accepts parameters like -F "name=contents". If you want the contents to
+  be read from a file, use <@filename> as contents. When specifying a file,
+  you can also specify the file content type by appending ';type=<mime type>'
+  to the file name. You can also post the contents of several files in one
+  field.  For example, the field name 'coolfiles' is used to send three files,
+  with different content types using the following syntax:
+
+        curl -F "coolfiles=@fil1.gif;type=image/gif,fil2.txt,fil3.html" \
+        http://www.post.com/postit.cgi
+
+  If the content-type is not specified, curl will try to guess from the file
+  extension (it only knows a few), or use the previously specified type (from
+  an earlier file if several files are specified in a list) or else it will
+  use the default type 'application/octet-stream'.
+
+  Emulate a fill-in form with -F. Let's say you fill in three fields in a
+  form. One field is a file name which to post, one field is your name and one
+  field is a file description. We want to post the file we have written named
+  "cooltext.txt". To let curl do the posting of this data instead of your
+  favourite browser, you have to read the HTML source of the form page and
+  find the names of the input fields. In our example, the input field names
+  are 'file', 'yourname' and 'filedescription'.
+
+        curl -F "file=@cooltext.txt" -F "yourname=Daniel" \
+             -F "filedescription=Cool text file with cool text inside" \
+             http://www.post.com/postit.cgi
+
+  To send two files in one post you can do it in two ways:
+
+  1. Send multiple files in a single "field" with a single field name:
+
+        curl -F "pictures=@dog.gif,cat.gif"
+
+  2. Send two fields with two field names:
+
+        curl -F "docpicture=@dog.gif" -F "catpicture=@cat.gif"
+
+  To send a field value literally without interpreting a leading '@'
+  or '<', or an embedded ';type=', use --form-string instead of
+  -F. This is recommended when the value is obtained from a user or
+  some other unpredictable source. Under these circumstances, using
+  -F instead of --form-string would allow a user to trick curl into
+  uploading a file.
+
+REFERRER
+
+  An HTTP request has the option to include information about which address
+  referred it to the actual page.  Curl allows you to specify the
+  referrer to be used on the command line. It is especially useful to
+  fool or trick stupid servers or CGI scripts that rely on that information
+  being available or contain certain data.
+
+        curl -e www.coolsite.com http://www.showme.com/
+
+  NOTE: The Referer: [sic] field is defined in the HTTP spec to be a full URL.
+
+USER AGENT
+
+  An HTTP request has the option to include information about the browser
+  that generated the request. Curl allows it to be specified on the command
+  line. It is especially useful to fool or trick stupid servers or CGI
+  scripts that only accept certain browsers.
+
+  Example:
+
+  curl -A 'Mozilla/3.0 (Win95; I)' http://www.nationsbank.com/
+
+  Other common strings:
+    'Mozilla/3.0 (Win95; I)'     Netscape Version 3 for Windows 95
+    'Mozilla/3.04 (Win95; U)'    Netscape Version 3 for Windows 95
+    'Mozilla/2.02 (OS/2; U)'     Netscape Version 2 for OS/2
+    'Mozilla/4.04 [en] (X11; U; AIX 4.2; Nav)'           NS for AIX
+    'Mozilla/4.05 [en] (X11; U; Linux 2.0.32 i586)'      NS for Linux
+
+  Note that Internet Explorer tries hard to be compatible in every way:
+    'Mozilla/4.0 (compatible; MSIE 4.01; Windows 95)'    MSIE for W95
+
+  Mozilla is not the only possible User-Agent name:
+    'Konqueror/1.0'             KDE File Manager desktop client
+    'Lynx/2.7.1 libwww-FM/2.14' Lynx command line browser
+
+COOKIES
+
+  Cookies are generally used by web servers to keep state information at the
+  client's side. The server sets cookies by sending a response line in the
+  headers that looks like 'Set-Cookie: <data>' where the data part then
+  typically contains a set of NAME=VALUE pairs (separated by semicolons ';'
+  like "NAME1=VALUE1; NAME2=VALUE2;"). The server can also specify for what
+  path the "cookie" should be used for (by specifying "path=value"), when the
+  cookie should expire ("expire=DATE"), for what domain to use it
+  ("domain=NAME") and if it should be used on secure connections only
+  ("secure").
+
+  If you've received a page from a server that contains a header like:
+        Set-Cookie: sessionid=boo123; path="/foo";
+
+  it means the server wants that first pair passed on when we get anything in
+  a path beginning with "/foo".
+
+  Example, get a page that wants my name passed in a cookie:
+
+        curl -b "name=Daniel" www.sillypage.com
+
+  Curl also has the ability to use previously received cookies in following
+  sessions. If you get cookies from a server and store them in a file in a
+  manner similar to:
+
+        curl --dump-header headers www.example.com
+
+  ... you can then in a second connect to that (or another) site, use the
+  cookies from the 'headers' file like:
+
+        curl -b headers www.example.com
+
+  While saving headers to a file is a working way to store cookies, it is
+  however error-prone and not the preferred way to do this. Instead, make curl
+  save the incoming cookies using the well-known netscape cookie format like
+  this:
+
+        curl -c cookies.txt www.example.com
+
+  Note that by specifying -b you enable the "cookie awareness" and with -L
+  you can make curl follow a location: (which often is used in combination
+  with cookies). So that if a site sends cookies and a location, you can
+  use a non-existing file to trigger the cookie awareness like:
+
+        curl -L -b empty.txt www.example.com
+
+  The file to read cookies from must be formatted using plain HTTP headers OR
+  as netscape's cookie file. Curl will determine what kind it is based on the
+  file contents.  In the above command, curl will parse the header and store
+  the cookies received from www.example.com.  curl will send to the server the
+  stored cookies which match the request as it follows the location.  The
+  file "empty.txt" may be a nonexistent file.
+
+  Alas, to both read and write cookies from a netscape cookie file, you can
+  set both -b and -c to use the same file:
+
+        curl -b cookies.txt -c cookies.txt www.example.com
+
+PROGRESS METER
+
+  The progress meter exists to show a user that something actually is
+  happening. The different fields in the output have the following meaning:
+
+  % Total    % Received % Xferd  Average Speed          Time             Curr.
+                                 Dload  Upload Total    Current  Left    Speed
+  0  151M    0 38608    0     0   9406      0  4:41:43  0:00:04  4:41:39  9287
+
+  From left-to-right:
+   %             - percentage completed of the whole transfer
+   Total         - total size of the whole expected transfer
+   %             - percentage completed of the download
+   Received      - currently downloaded amount of bytes
+   %             - percentage completed of the upload
+   Xferd         - currently uploaded amount of bytes
+   Average Speed
+   Dload         - the average transfer speed of the download
+   Average Speed
+   Upload        - the average transfer speed of the upload
+   Time Total    - expected time to complete the operation
+   Time Current  - time passed since the invoke
+   Time Left     - expected time left to completion
+   Curr.Speed    - the average transfer speed the last 5 seconds (the first
+                   5 seconds of a transfer is based on less time of course.)
+
+  The -# option will display a totally different progress bar that doesn't
+  need much explanation!
+
+SPEED LIMIT
+
+  Curl allows the user to set the transfer speed conditions that must be met
+  to let the transfer keep going. By using the switch -y and -Y you
+  can make curl abort transfers if the transfer speed is below the specified
+  lowest limit for a specified time.
+
+  To have curl abort the download if the speed is slower than 3000 bytes per
+  second for 1 minute, run:
+
+        curl -Y 3000 -y 60 www.far-away-site.com
+
+  This can very well be used in combination with the overall time limit, so
+  that the above operation must be completed in whole within 30 minutes:
+
+        curl -m 1800 -Y 3000 -y 60 www.far-away-site.com
+
+  Forcing curl not to transfer data faster than a given rate is also possible,
+  which might be useful if you're using a limited bandwidth connection and you
+  don't want your transfer to use all of it (sometimes referred to as
+  "bandwidth throttle").
+
+  Make curl transfer data no faster than 10 kilobytes per second:
+
+        curl --limit-rate 10K www.far-away-site.com
+
+    or
+
+        curl --limit-rate 10240 www.far-away-site.com
+
+  Or prevent curl from uploading data faster than 1 megabyte per second:
+
+        curl -T upload --limit-rate 1M ftp://uploadshereplease.com
+
+  When using the --limit-rate option, the transfer rate is regulated on a
+  per-second basis, which will cause the total transfer speed to become lower
+  than the given number. Sometimes of course substantially lower, if your
+  transfer stalls during periods.
+
+CONFIG FILE
+
+  Curl automatically tries to read the .curlrc file (or _curlrc file on win32
+  systems) from the user's home dir on startup.
+
+  The config file could be made up with normal command line switches, but you
+  can also specify the long options without the dashes to make it more
+  readable. You can separate the options and the parameter with spaces, or
+  with = or :. Comments can be used within the file. If the first letter on a
+  line is a '#'-symbol the rest of the line is treated as a comment.
+
+  If you want the parameter to contain spaces, you must enclose the entire
+  parameter within double quotes ("). Within those quotes, you specify a
+  quote as \".
+
+  NOTE: You must specify options and their arguments on the same line.
+
+  Example, set default time out and proxy in a config file:
+
+        # We want a 30 minute timeout:
+        -m 1800
+        # ... and we use a proxy for all accesses:
+        proxy = proxy.our.domain.com:8080
+
+  White spaces ARE significant at the end of lines, but all white spaces
+  leading up to the first characters of each line are ignored.
+
+  Prevent curl from reading the default file by using -q as the first command
+  line parameter, like:
+
+        curl -q www.thatsite.com
+
+  Force curl to get and display a local help page in case it is invoked
+  without URL by making a config file similar to:
+
+        # default url to get
+        url = "http://help.with.curl.com/curlhelp.html"
+
+  You can specify another config file to be read by using the -K/--config
+  flag. If you set config file name to "-" it'll read the config from stdin,
+  which can be handy if you want to hide options from being visible in process
+  tables etc:
+
+        echo "user = user:passwd" | curl -K - http://that.secret.site.com
+
+EXTRA HEADERS
+
+  When using curl in your own very special programs, you may end up needing
+  to pass on your own custom headers when getting a web page. You can do
+  this by using the -H flag.
+
+  Example, send the header "X-you-and-me: yes" to the server when getting a
+  page:
+
+        curl -H "X-you-and-me: yes" www.love.com
+
+  This can also be useful in case you want curl to send a different text in a
+  header than it normally does. The -H header you specify then replaces the
+  header curl would normally send. If you replace an internal header with an
+  empty one, you prevent that header from being sent. To prevent the Host:
+  header from being used:
+
+        curl -H "Host:" www.server.com
+
+FTP and PATH NAMES
+
+  Do note that when getting files with the ftp:// URL, the given path is
+  relative the directory you enter. To get the file 'README' from your home
+  directory at your ftp site, do:
+
+        curl ftp://user:passwd@my.site.com/README
+
+  But if you want the README file from the root directory of that very same
+  site, you need to specify the absolute file name:
+
+        curl ftp://user:passwd@my.site.com//README
+
+  (I.e with an extra slash in front of the file name.)
+
+SFTP and SCP and PATH NAMES
+
+  With sftp: and scp: URLs, the path name given is the absolute name on the
+  server. To access a file relative to the remote user's home directory,
+  prefix the file with /~/ , such as:
+
+        curl -u $USER sftp://home.example.com/~/.bashrc
+
+FTP and firewalls
+
+  The FTP protocol requires one of the involved parties to open a second
+  connection as soon as data is about to get transferred. There are two ways to
+  do this.
+
+  The default way for curl is to issue the PASV command which causes the
+  server to open another port and await another connection performed by the
+  client. This is good if the client is behind a firewall that doesn't allow
+  incoming connections.
+
+        curl ftp.download.com
+
+  If the server, for example, is behind a firewall that doesn't allow connections
+  on ports other than 21 (or if it just doesn't support the PASV command), the
+  other way to do it is to use the PORT command and instruct the server to
+  connect to the client on the given IP number and port (as parameters to the
+  PORT command).
+
+  The -P flag to curl supports a few different options. Your machine may have
+  several IP-addresses and/or network interfaces and curl allows you to select
+  which of them to use. Default address can also be used:
+
+        curl -P - ftp.download.com
+
+  Download with PORT but use the IP address of our 'le0' interface (this does
+  not work on windows):
+
+        curl -P le0 ftp.download.com
+
+  Download with PORT but use 192.168.0.10 as our IP address to use:
+
+        curl -P 192.168.0.10 ftp.download.com
+
+NETWORK INTERFACE
+
+  Get a web page from a server using a specified port for the interface:
+
+        curl --interface eth0:1 http://www.netscape.com/
+
+  or
+
+        curl --interface 192.168.1.10 http://www.netscape.com/
+
+HTTPS
+
+  Secure HTTP requires SSL libraries to be installed and used when curl is
+  built. If that is done, curl is capable of retrieving and posting documents
+  using the HTTPS protocol.
+
+  Example:
+
+        curl https://www.secure-site.com
+
+  Curl is also capable of using your personal certificates to get/post files
+  from sites that require valid certificates. The only drawback is that the
+  certificate needs to be in PEM-format. PEM is a standard and open format to
+  store certificates with, but it is not used by the most commonly used
+  browsers (Netscape and MSIE both use the so called PKCS#12 format). If you
+  want curl to use the certificates you use with your (favourite) browser, you
+  may need to download/compile a converter that can convert your browser's
+  formatted certificates to PEM formatted ones. This kind of converter is
+  included in recent versions of OpenSSL, and for older versions Dr Stephen
+  N. Henson has written a patch for SSLeay that adds this functionality. You
+  can get his patch (that requires an SSLeay installation) from his site at:
+  http://www.drh-consultancy.demon.co.uk/
+
+  Example on how to automatically retrieve a document using a certificate with
+  a personal password:
+
+        curl -E /path/to/cert.pem:password https://secure.site.com/
+
+  If you neglect to specify the password on the command line, you will be
+  prompted for the correct password before any data can be received.
+
+  Many older SSL-servers have problems with SSLv3 or TLS, which newer versions
+  of OpenSSL etc use, therefore it is sometimes useful to specify what
+  SSL-version curl should use. Use -3, -2 or -1 to specify that exact SSL
+  version to use (for SSLv3, SSLv2 or TLSv1 respectively):
+
+        curl -2 https://secure.site.com/
+
+  Otherwise, curl will first attempt to use v3 and then v2.
+
+  To use OpenSSL to convert your favourite browser's certificate into a PEM
+  formatted one that curl can use, do something like this:
+
+    In Netscape, you start with hitting the 'Security' menu button.
+
+    Select 'certificates->yours' and then pick a certificate in the list
+
+    Press the 'Export' button
+
+    enter your PIN code for the certs
+
+    select a proper place to save it
+
+    Run the 'openssl' application to convert the certificate. If you cd to the
+    openssl installation, you can do it like:
+
+     # ./apps/openssl pkcs12 -in [file you saved] -clcerts -out [PEMfile]
+
+    In Firefox, select Options, then Advanced, then the Encryption tab,
+    View Certificates. This opens the Certificate Manager, where you can
+    Export. Be sure to select PEM for the Save as type.
+
+    In Internet Explorer, select Internet Options, then the Content tab, then
+    Certificates. Then you can Export, and depending on the format you may
+    need to convert to PEM.
+
+    In Chrome, select Settings, then Show Advanced Settings. Under HTTPS/SSL
+    select Manage Certificates.
+
+RESUMING FILE TRANSFERS
+
+ To continue a file transfer where it was previously aborted, curl supports
+ resume on HTTP(S) downloads as well as FTP uploads and downloads.
+
+ Continue downloading a document:
+
+        curl -C - -o file ftp://ftp.server.com/path/file
+
+ Continue uploading a document(*1):
+
+        curl -C - -T file ftp://ftp.server.com/path/file
+
+ Continue downloading a document from a web server(*2):
+
+        curl -C - -o file http://www.server.com/
+
+ (*1) = This requires that the FTP server supports the non-standard command
+        SIZE. If it doesn't, curl will say so.
+
+ (*2) = This requires that the web server supports at least HTTP/1.1. If it
+        doesn't, curl will say so.
+
+TIME CONDITIONS
+
+ HTTP allows a client to specify a time condition for the document it
+ requests. It is If-Modified-Since or If-Unmodified-Since. Curl allows you to
+ specify them with the -z/--time-cond flag.
+
+ For example, you can easily make a download that only gets performed if the
+ remote file is newer than a local copy. It would be made like:
+
+        curl -z local.html http://remote.server.com/remote.html
+
+ Or you can download a file only if the local file is newer than the remote
+ one. Do this by prepending the date string with a '-', as in:
+
+        curl -z -local.html http://remote.server.com/remote.html
+
+ You can specify a "free text" date as condition. Tell curl to only download
+ the file if it was updated since January 12, 2012:
+
+        curl -z "Jan 12 2012" http://remote.server.com/remote.html
+
+ Curl will then accept a wide range of date formats. You always make the date
+ check the other way around by prepending it with a dash '-'.
+
+DICT
+
+  For fun try
+
+        curl dict://dict.org/m:curl
+        curl dict://dict.org/d:heisenbug:jargon
+        curl dict://dict.org/d:daniel:web1913
+
+  Aliases for 'm' are 'match' and 'find', and aliases for 'd' are 'define'
+  and 'lookup'. For example,
+
+        curl dict://dict.org/find:curl
+
+  Commands that break the URL description of the RFC (but not the DICT
+  protocol) are
+
+        curl dict://dict.org/show:db
+        curl dict://dict.org/show:strat
+
+  Authentication is still missing (but this is not required by the RFC)
+
+LDAP
+
+  If you have installed the OpenLDAP library, curl can take advantage of it
+  and offer ldap:// support.
+
+  LDAP is a complex thing and writing an LDAP query is not an easy task. I do
+  advise you to dig up the syntax description for that elsewhere. Two places
+  that might suit you are:
+
+  Netscape's "Netscape Directory SDK 3.0 for C Programmer's Guide Chapter 10:
+  Working with LDAP URLs":
+  http://developer.netscape.com/docs/manuals/dirsdk/csdk30/url.htm
+
+  RFC 2255, "The LDAP URL Format" http://curl.haxx.se/rfc/rfc2255.txt
+
+  To show you an example, this is how I can get all people from my local LDAP
+  server that has a certain sub-domain in their email address:
+
+        curl -B "ldap://ldap.frontec.se/o=frontec??sub?mail=*sth.frontec.se"
+
+  If I want the same info in HTML format, I can get it by not using the -B
+  (enforce ASCII) flag.
+
+ENVIRONMENT VARIABLES
+
+  Curl reads and understands the following environment variables:
+
+        http_proxy, HTTPS_PROXY, FTP_PROXY
+
+  They should be set for protocol-specific proxies. General proxy should be
+  set with
+
+        ALL_PROXY
+
+  A comma-separated list of host names that shouldn't go through any proxy is
+  set in (only an asterisk, '*' matches all hosts)
+
+        NO_PROXY
+
+  If the host name matches one of these strings, or the host is within the
+  domain of one of these strings, transactions with that node will not be
+  proxied.
+
+
+  The usage of the -x/--proxy flag overrides the environment variables.
+
+NETRC
+
+  Unix introduced the .netrc concept a long time ago. It is a way for a user
+  to specify name and password for commonly visited FTP sites in a file so
+  that you don't have to type them in each time you visit those sites. You
+  realize this is a big security risk if someone else gets hold of your
+  passwords, so therefore most unix programs won't read this file unless it is
+  only readable by yourself (curl doesn't care though).
+
+  Curl supports .netrc files if told to (using the -n/--netrc and
+  --netrc-optional options). This is not restricted to just FTP,
+  so curl can use it for all protocols where authentication is used.
+
+  A very simple .netrc file could look something like:
+
+        machine curl.haxx.se login iamdaniel password mysecret
+
+CUSTOM OUTPUT
+
+  To better allow script programmers to get to know about the progress of
+  curl, the -w/--write-out option was introduced. Using this, you can specify
+  what information from the previous transfer you want to extract.
+
+  To display the amount of bytes downloaded together with some text and an
+  ending newline:
+
+        curl -w 'We downloaded %{size_download} bytes\n' www.download.com
+
+KERBEROS FTP TRANSFER
+
+  Curl supports kerberos4 and kerberos5/GSSAPI for FTP transfers. You need
+  the kerberos package installed and used at curl build time for it to be
+  available.
+
+  First, get the krb-ticket the normal way, like with the kinit/kauth tool.
+  Then use curl in way similar to:
+
+        curl --krb private ftp://krb4site.com -u username:fakepwd
+
+  There's no use for a password on the -u switch, but a blank one will make
+  curl ask for one and you already entered the real password to kinit/kauth.
+
+TELNET
+
+  The curl telnet support is basic and very easy to use. Curl passes all data
+  passed to it on stdin to the remote server. Connect to a remote telnet
+  server using a command line similar to:
+
+        curl telnet://remote.server.com
+
+  And enter the data to pass to the server on stdin. The result will be sent
+  to stdout or to the file you specify with -o.
+
+  You might want the -N/--no-buffer option to switch off the buffered output
+  for slow connections or similar.
+
+  Pass options to the telnet protocol negotiation, by using the -t option. To
+  tell the server we use a vt100 terminal, try something like:
+
+        curl -tTTYPE=vt100 telnet://remote.server.com
+
+  Other interesting options for it -t include:
+
+   - XDISPLOC=<X display> Sets the X display location.
+
+   - NEW_ENV=<var,val> Sets an environment variable.
+
+  NOTE: The telnet protocol does not specify any way to login with a specified
+  user and password so curl can't do that automatically. To do that, you need
+  to track when the login prompt is received and send the username and
+  password accordingly.
+
+PERSISTENT CONNECTIONS
+
+  Specifying multiple files on a single command line will make curl transfer
+  all of them, one after the other in the specified order.
+
+  libcurl will attempt to use persistent connections for the transfers so that
+  the second transfer to the same host can use the same connection that was
+  already initiated and was left open in the previous transfer. This greatly
+  decreases connection time for all but the first transfer and it makes a far
+  better use of the network.
+
+  Note that curl cannot use persistent connections for transfers that are used
+  in subsequence curl invokes. Try to stuff as many URLs as possible on the
+  same command line if they are using the same host, as that'll make the
+  transfers faster. If you use an HTTP proxy for file transfers, practically
+  all transfers will be persistent.
+
+MULTIPLE TRANSFERS WITH A SINGLE COMMAND LINE
+
+  As is mentioned above, you can download multiple files with one command line
+  by simply adding more URLs. If you want those to get saved to a local file
+  instead of just printed to stdout, you need to add one save option for each
+  URL you specify. Note that this also goes for the -O option (but not
+  --remote-name-all).
+
+  For example: get two files and use -O for the first and a custom file
+  name for the second:
+
+    curl -O http://url.com/file.txt ftp://ftp.com/moo.exe -o moo.jpg
+
+  You can also upload multiple files in a similar fashion:
+
+    curl -T local1 ftp://ftp.com/moo.exe -T local2 ftp://ftp.com/moo2.txt
+
+IPv6
+
+  curl will connect to a server with IPv6 when a host lookup returns an IPv6
+  address and fall back to IPv4 if the connection fails. The --ipv4 and --ipv6
+  options can specify which address to use when both are available. IPv6
+  addresses can also be specified directly in URLs using the syntax:
+
+    http://[2001:1890:1112:1::20]/overview.html
+
+  When this style is used, the -g option must be given to stop curl from
+  interpreting the square brackets as special globbing characters.  Link local
+  and site local addresses including a scope identifier, such as fe80::1234%1,
+  may also be used, but the scope portion must be numeric and the percent
+  character must be URL escaped. The previous example in an SFTP URL might
+  look like:
+
+    sftp://[fe80::1234%251]/
+
+  IPv6 addresses provided other than in URLs (e.g. to the --proxy, --interface
+  or --ftp-port options) should not be URL encoded.
+
+METALINK
+
+  Curl supports Metalink (both version 3 and 4 (RFC 5854) are supported), a way
+  to list multiple URIs and hashes for a file. Curl will make use of the mirrors
+  listed within for failover if there are errors (such as the file or server not
+  being available). It will also verify the hash of the file after the download
+  completes. The Metalink file itself is downloaded and processed in memory and
+  not stored in the local file system.
+
+  Example to use a remote Metalink file:
+
+    curl --metalink http://www.example.com/example.metalink
+
+  To use a Metalink file in the local file system, use FILE protocol (file://):
+
+    curl --metalink file://example.metalink
+
+  Please note that if FILE protocol is disabled, there is no way to use a local
+  Metalink file at the time of this writing. Also note that if --metalink and
+  --include are used together, --include will be ignored. This is because including
+  headers in the response will break Metalink parser and if the headers are included
+  in the file described in Metalink file, hash check will fail.
+
+MAILING LISTS
+
+  For your convenience, we have several open mailing lists to discuss curl,
+  its development and things relevant to this. Get all info at
+  http://curl.haxx.se/mail/. Some of the lists available are:
+
+  curl-users
+
+    Users of the command line tool. How to use it, what doesn't work, new
+    features, related tools, questions, news, installations, compilations,
+    running, porting etc.
+
+  curl-library
+
+    Developers using or developing libcurl. Bugs, extensions, improvements.
+
+  curl-announce
+
+    Low-traffic. Only receives announcements of new public versions. At worst,
+    that makes something like one or two mails per month, but usually only one
+    mail every second month.
+
+  curl-and-php
+
+    Using the curl functions in PHP. Everything curl with a PHP angle. Or PHP
+    with a curl angle.
+
+  curl-and-python
+
+    Python hackers using curl with or without the python binding pycurl.
+
+  Please direct curl questions, feature requests and trouble reports to one of
+  these mailing lists instead of mailing any individual.