New IM Code for Xbase++ 2.0

[rdonnay]

Here is the first pass at IMCLIENT and IMSERVER for Xbase++ 2.0.

This eliminates the need for Xb2Net.

It uses 3 new classes in DCLIPX.DLL (_DCWEB.PRG) named DC_WebSocketClient, DC_WebSocketHandler and DC_WebSocketData.

IMCLIENT20.* and IMSERVER20.* use the Xbase++ 2.0 Internet capabilities.
IMCLIENT.* and IMSERVER.* still use the Xb2Net Internet capabilities.

The new system is based on HttpEndPoint as the http server. It talks to DC_WebSocketHander to handle all requests from the client.

Unzip IMCLIENT20.ZIP into your \exp20\source\imclient folder and run BUILD20.BAT to build IMCLIENT.EXE, IMCLIENT20.EXE, IMCLIENT.DLL and IMCLIENT20.DLL

Unzip IMSERVER20.ZIP into your \exp20\source\imserver.folder and run BUILD20.BAT to build IMSERVER.EXE and IMSERVER20.EXE.

Unzip DCLIPX20.ZIP into your \exp20\source\dclipx folder and run BUILD20.BAT to rebuild DCLIPX.DLL.