INT-2830 Resolve Class Tangle

MessageGroupStore <-> MessageGroupCallback

Change callback to be an inner interface of the MGS.
INT-2829 Fix Class Tangle in IP Module

3 way tangle between TcpSender, TcpConnection, TcpMessageMapper

Clean up interfaces (remove setters); add top-level support
classes for TcpConnection, TcpConnectionInterceptor.
INT-2829 Remove TCP Package Tangle

tcp.connection <-> tcp.connection.support

Remove ...connection.support package - move classes
to ...connection.