Ability to register new incoming network events (based on exisiting one) added. Modify-only network events are possible (eg. add some text each message, but don't create any new global event). Events creation can be chained.
Examples of new network events classes are in New Events Example plugin.
Events from src/gajim.py now all go through Global Events Dispatcher and only through it (easy to modify, in chain, data passed with them).
Events previously generated for D-Bus support in remote_control.py go through Global Events Dispatcher now - this means any plugin can subscribe to them.
Implemented D-Bus support plugin based on remote_control.py.
