added syntax version (required for protobuf 3)

	download completed state
client-qt:
	added "download completed" subscription and status support
server:
	module_curl:
		used events api in core for download state changes
	core:
		download completed event support for modules

updated copyrights (new year)
server:
	started implementation of api for module events (module should be able to fire event which will be delivered to clients which have subscribed for this event type)

	added download deleted event
	small cleanup
server:
	implemented "download_deleted" event
client:
	started work on download state change events handling

	added download_state change structure (used in download state changes event
from server)
client-qt:
	subscription to download state changes events
server:
	basic implementation of download state changes events

TODO: use single structure for download_state_changes in messages instead of all
separate ones.

	tiny enum value names correction
server:
	event subscription subsystem:
		a bit of implementation of repeated event type

	a bit of work with "client_event_subscription_request"
	some comments
server:
	event subsystem:
		event's object class skeleton
		very basic event subscription handler

	split to multiple proto files

	some work with event supscription proto part (unfinished)

	use repeated instead of optional fields for download_start_request, download_stop_request, download_delete_request, download_action_request - this allow to execute same action on multiple downloads via one message which is much more efficient than send
message for each download
client-qt:
	basic download menu (without dynamic actions)
	implemented start/stop/delete proto part
server:
	core:
		basic protocol implementation for: CLIENT_DOWNLOAD_INFO_REQUEST, CLIENT_DOWNLOAD_START, CLIENT_DOWNLOAD_STOP, CLIENT_DOWNLOAD_DELETE