Refactored XMPPStatus a bit to remove initStatus and to always show status_message
initStatus is still usefull when we have undefined initial status.

Also set bare_jid, domain and muc_domain on the xmppchat obj and not the
connection obj.
Add support for sending nick along with subscription request
Send nick along with subscription request.

Additionally:
It's not feasible to get the current user's fullname from a vCard all the time,
so we still get it from the DOM for now.
Better handling of user avatar. Don't create canvas el if there's no avatar.

Also, don't fetch vCards in rosterHandler. This could be very expensive for
large rosters, instead we'll fetch them when a user comes online.
Don't check the cache in getVCard since we don't call it so often anymore
Bugfix. Set up the RosterView after the Controlbox

Also, don't save subscription requesting contacts to cache.