Add premessage-deflate extension handler for HTTP WebSocket

Add premessage-deflate extension handler for HTTP WebSocket.

Motivation:
- Need to compress HTTP WebSocket frames payload.

Modifications:
- Remove UTF8 checking of WebSocketFrames from frame decoder in order to
allow compressed frames to go to the next handler.
- Add a WebsocketPremessageDeflateHandler to initialize the frame deflater/inflater if client is compatible with deflate extension.

Result:
First version of the implementation for feedback.
@fboucher38 even if the JdkZlibEncoder does ignore them these will still be used when jzlib is used. As far as I can tell there is no way to specify this stuff when using java.util.Deflater.