[Engine-XMPP] "/contact rename jid" clears the nickname of the contact
[Frontend-GNOME-XMPP] New property that specifies whether the XmppGroupChat is the contactlist or a muc
[Frontend-GNOME(-XMPP)] Allow direct editing of contacts' nicknames in the contactlist
Merge pull request #66 from oli-obk/feature/graphical_rename