Rework implicit forwards and receiver to first pipe in pipeline

Currently everything gets a implicit forward in the xml-to-json-parser. That is the wrong place. Creating a new node in the canvas does not create a new implicit forward. Only when you close and open the adapter it gets shown.

IfPipe also gets implicit forward. It is a bit strange because it isn't shown until a handle gets created, than it shows up. So it looks like you can have an implicit exception forward, which is not the case in this instance.

It should be dashed (like in design!!)

It should not be possible to change the implicit forward on the receiver. Maybe that should be another issue.