WebSockets - first version.

The implementation is mostly complete, and ready for the review.
Metrics are still to be implemented.
Remove WebSocketFrame wrapper classes.
WebSocket metrics.
Update WebSocket example.
Correct implementation of WebSocketClientServerTest.
After code review updates.
Merge pull request #196 from tbak/features/websocket

WebSockets - implementation proposal for issue #125
Merge branch 'master' of https://github.com/Netflix/RxNetty
Added missing copyrights