Move Roster and Chat(Manager) code into their own packages within the new smack-im subproject. Apply Manager pattern to Roster. Fixes SMACK-637.
- De-duplicate code by moving it into AbstractXMPPConnection - Introduce TopLevelStreamElement as superclass for all XMPP stream elements. - Add SynchronizationPoint, ParserUtils - Add ParserUtils Fixes SMACK-333 and SMACK-521