Fix disconnect via keepalive, invoke DispatchMessageQueue to handle received messages

[Tossrock]

Connections are automatically dropped after a timeout due to this bug in C#'s handling of websocket traffic. This should fix Issue 92.

Also actually invokes DispatchMessageQueue when receiving a message, so that OnMessage handlers actually get called. Seems that there was code commented out on L672 - L676 in WebSocket.cs without the correct replacement being added. This causes OnMessage events to behave as expected.