Gerrit integration with Git on master side

Conflicts:
	master/docs/relnotes/index.rst
Implement Jabber support

We' re using the wokkel library [1] here, which provides some
enhancement to the Jabber/XMPP implementation found in Twisted Words.

Eventually wokkel is supposed to be merged into Twisted.

[1] http://wokkel.ik.nu/