- all signal storage data extracted to the separate class MSignalStore;
- MSignalSession added to handle session ciphers
- signal store callbacks registered
- all libsignal related code moved to signal.cpp

- first version that registers ok in the phone (YAHOO!!);
- the rest of legacy code removed;
- class WAJid introduced to handle various perversions;
- ServerThread behavior changed to use global variables instead of locals;
- IQ processing core extracted to the separate module;
- added <stream:error> processing