BUG-542 - adding overall statictics

- temporary extended messageSpy code
- added logging to rpc threadPool - afterExecution
- cleaned imports
- deprecated hard coded configurations for OFJava SwitchConnectionProvider
- simplified signature of MessageSpy
- added messageSpy and rpcPool into SessionManager

Change-Id: If41e33c885dab0907fdf642ad1f483d93f74b19c
Signed-off-by: Michal Rehak <mirehak@cisco.com>