Add new icons for opened and closed groups.
We now have a functioning mockup of contact groups. updates #83
Rename 'enable_message_carbons' to 'message_carbons'
Some initial refactoring to support roster groups. updates #83

Made sure that the non-group usecase is still covered.
Possible fix for issue #175.

Make sure contact's chat_status attr is saved.

Updates #175
Manage fontawesome via bower
Remove unused resources
Allow group headings to be toggleable. updates #83
JShint doesn't like functions inside loops
Add tests for toggleable headings. updates #83
Some refactoring of RosterView and skeleton for groups test
Merge branch 'master' into groups

Conflicts:
	converse.js
Fix width for pending and requesting contacts
Tweak activation script
Bugfix. Handle case where user accepts request.

But other user is not online to quickly subscribe back.
New entry in .gitignore
Bugfix.

Can't know whether existing roster item is already shown under the existing group.
Refactor updateRoster and renderRosterItemView

Simplified updateRoster by removing the duplicate checks that RosterItemView's
render method was doing.
Some sorting optimizations

* Differentiate between adding new roster items and rendering existing ones.
* Also, only sort pending and requesting contacts once they've all been added
  (similar to what was already being done with existing contacts)
Clean up the initialize method of RosterView

by moving event handers out