Debugger gets confused if multiple resources are opened

[lschuetze]

If there are multiple resources opened the debugger gets confused. That is due to the mapping is hold on the IModel. If those two resources have the same model their mappings get overwritten. There have to be a resource dependent mapping on the IModel.

So there are several things to do:

• change the IModel interface to provide access to resource specific mappings
• make the scala post-parser to use this new interfaces
• make the debugger to use the new interface of the IModel