Debugger is broken in new editor / model

the following functions have to be restored:

1. set / unset / enable / disable breakpoints (also conditional)
2. flag set breakpoints in the editor figures header
3. only open the context file in diagram when its not open already
4. use the local file for debugging, not the remote one
5. breakpoints should have a key consisting of context id, route id and eip figure id --> route id not needed as ID is unique over whole xml file
6. repair broken highlighting of nodes while stepping
7. check why suspended nodes are not always highlighted