*Define custom error codes
*generate errors and propagate them to the subscribers (client or server)
*The client subscriber must override the "Handle Last Ack Core" method and from that extract the error of the client shutting down
*The subscriber of the server must override the "Handle Error" method to catch the specific errors*
* If an unknown error leads to an invalid Listener reference the server will now shutdown, because it would then kill possibly working connections to clients, but it will stop accepting definitions of new services by throwing a specific error

…notified of errors and will need to override the method Handle Error to catch them. Updated license and release notes

* The errors generated by the WebSocket Server are now reported to the subscriber and not to the caller, hence they will not even pass through the Server Manager if used
* Added custom errors generated by the Start Server, Stop Server, Add Service WebSocket Server methods
* improved documentation

* we now report the Server URI or the Service Name in the error source when we have problems launching/stopping a server or adding a service

Better structure for the function's palette, to improve readability of the palette all the actors now have the same icon color

* Solved a bug whereby  the WebSocket Server actor, upon handling an error, forwards it to the subscriber but doesnt clear it resulting in an endless lopp in the "Actor Core.vi" (Closes #9)

* Client Error forwarding bug  fixed and tested  (Closes #9)
* VIPM package built

Added VIPM package installation instructions and contributing guidelines.