ClientWebSocket: SendAsync endOfMessage inverted.

endOfMessage should indicate whether or not additional message parts will follow the current one. Currently, the meaning in ClientWebSocket.cs is inverted: !endOfMessage indicates that no more parts will follow the current one.

See the WebSockets RFC, 'frame-fin' at the top of http://tools.ietf.org/html/rfc6455#page-31.
Also see the MSDN docs for SendAsync: http://msdn.microsoft.com/en-us/library/system.net.websockets.websocket.sendasync(v=vs.110).aspx
Test ClientWebSocket.SendAsync EndOfMessage
Merge branch 'patch-1' of https://github.com/ReubenBond/mono into ReubenBond-patch-1
[System] Fixed formatting of new ClientWebSocket test and disabled it

We need to have an implementation for HttpListenerContext.AcceptWebSocketAsync () first before it works.