friends list. Widgets are sorted upon being added to the friends list in
the first place, and re-sorted if a user changes their name, or if a
user is given an alias.
-Friend now inherits from QObject
-Friend objects now emit a signal when their display name is changed
-FriendListWidget::moveWidget() is now a slot
Instead of names. Fixes#603
Groupchats still use names internally, since there's currently no way to get a chat member's public key throught the toxcore API
