IRIS EchoServer for WebSockets

This is a coding example working on IRIS 2020.1 and on Caché 2018.1.3 
It will not be kept in sync with new versions      
It is also NOT serviced by InterSystems Support !   

In Caché you had an example of a WebSocket Server in namespace SAMPLES
With IRIS the samples are gone and require additional installation effort.

So I refurbished the code with some useful additions:

• independent of namespace
• timeout control from client
• readable communication log

This contains 2 classes:

• rcc.EchoServer.cls
• rcc.WSScsp.cls for testing. Called from Browser by
  http://localhost:52773/csp/user/rcc.WSScsp.cls

The server is essential for the 'native' WebSocket Client Demo