New JabberProtocol implementation

[ForNeVeR]

We need a JabberProtocol reimplementation or wrapper or component that:

1. Will grant us throttling on sending every packet to the server (including reconnection attempts and room joins; see Sometimes actors aren't disposed on error #407).
2. Will not fall apart on problems with room joining; see "Let it fall" strategy for room joining #377 and Move room login to the room actor #358.
3. Will provide an exception-safe connection; see Unreliable start #313 and "Not connected to server" when trying to send a message #383.
4. Will provide an ability to adapt to threading model of the underlying library (I suspect that Smack needs to be used in a single-threaded apartment); remember that we'll want to replace Smack in scope of Migrate to Babbler XMPP library #410.
5. Will somewhat abstract the protocol interface, see Abstract protocol #309.
6. Shouldn't be tightly coupled with Akka,
7. Will be covered by a plenty of tests.
8. Will not suck.