First step to bring Stomp into rev 1.1+;

Moved Stomp's ack method to the Message class.  Added a nack method to compliment ack.  nack requires version 1.1+, so I included helper methods in Stomp to find that version.  This will help allow some of the newer frames in the Stomp 1.1+ Protocol.

If I happen to run into other STOMP protocol issues during my current project, I'll attempt to update things as I go a long.

There is also a little bit of formatting clean-up removing new lines.