Add User + GroupChatUser objects.
Add some JavaDoc.
Merge pull request #241 from csmith/master

Remove some more Server useages.
Merge pull request #240 from greboid/awaymessages

Add User + GroupChatUser objects.
Remove more usages of Server.

This adds a sendLine method to Connection, which is a bit icky,
but is useful when the end-user is supplying lines to pass
directly to the underlying connection.