FeatureRequest: virtualHandler.on() should have also a "set" event.

[mschaeffler]

The ".on" event handler of virtual components should also have a "set" event, so that you could also get every setting and not only changes of the virtual component.

Here is one example:

const enum200 = Virtual.getHandle( "enum:200" );
enum200.on( "set",
    function(event)
    {
        print( event.value );
        if( event.value === "S" )
        {
            switchOn( "S" );
        }
        else if( event.value === "D" )
        {
            switchOn( "D" );
        }
        else if( event.value === "L" )
        {
            switchOn( "L" );
        }
        else if( event.value === "-" )
        {
            switchOff();
        }
    }
);

At the moment I'm simulating this by subscribing to the MQTT topic ".../rpc" and checking the method value, but this is quite a hack and works just with changes via MQTT.