updates #83

by moving event handers out

* 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)

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

Can't know whether existing roster item is already shown under the existing group.

But other user is not online to quickly subscribe back.

Conflicts:
	converse.js

Assignment to writable property `style.height` instead of readonly `offsetHeight`.

Fixes #196.

Make sure contact's chat_status attr is saved.

Updates #175

Make sure contact's chat_status attr is saved.

Updates #175

Made sure that the non-group usecase is still covered.

This fix breaks compatibility with IE8