added .user into ignore list
fixed  context early disposal  in WebSocketClient
Merge pull request #1 from segor/master

merge segor's fork
fixed WebSocketClient.Disconnect().
Avoids null-reference exception, when underlying socket is not connected.
Socket disconnect event is sent to user code on client side.
Used to indicate when server shuts down.
Made compileable under Monodevelop 2.8.6.3
Added some settings in csproj and .gitignore.
Fixed opcode for close frame in WebSocketClient
Added Handler.FastDirectSendingMode.

When FastDirectSendingMode is set to true, the send-threads are not started.
Messages are then sent directly from the multithreaded application to
the underlaying socket buffer. The Send method may block a short time
until the previous send operation has copied its data do the socket buffer.
There is a considerable speed increase for applications needing
fast roundtrip times and have a small number of clients:
    FastDirectSendingMode = false:   33 request+responses per second - caused by a delay of 10ms in every dequeue operation.
    FastDirectSendingMode = true:  2500 request+responses per second
Skip pending send operations when disconnecting a client.
Removed unused method 'DoReceive'.
Added static methods to shutdown Alchemy threads.
Documented the strange behavour of WebSocketServer.Dispose().
Fixed client disconnect sequence.
Added CancellationSource to context;
Added asynchronous connect operation to client;
Added LatestException to UserContext.
This improves WebSocketClient connect and disconnect.
Corrected CR/LF.
WebSocketClient: prevented null exception on disconnect.
Fixed threading issues when receiving many messages in client. And when sending many messages in server or client.
Fixed integration tests ClientServerSubProtocol.
Support successive messages in the same receive buffer (server and client side).
Support breakpoints when starting unit tests from visual studio.
Fixed close message from server to client.
Support partially received headers on server and client side.
Fixed reset of FrameHeader.IsEnd.
Fixed client disconnect (make it ready for next connect).
Fixed WebSocketServer.Clients (count).
Fixed and improved integration test ClientSendDataConcurrent.
Added integration test ClientSendMultipleMessages.
Improved TCPServer: Use asynchronous BeginAcceptTcpClient instead of looping in a threadpool thread.