Hybi09 protocol fix

Hi! 
Not sure am I right, but Hybi09 draft requires add the header "Sec-WebSocket-Protocol" to the server response if the header was specified in request (http://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-09#section-11.9).

One of the native websocket clients (with Hiby09 implementation) whom I encountered, wasn't worked without this header.