feature: Add Progress Listener for Model Building

[msteinbeck]

Using Spoon to create a model for large size projects takes quite some time. Thus, I would like to attach some sort of progress listener to the Launcher class allowing me to track the current progress while creating a model. The progress listener should be able to distinguish between source compilation (JDT) and model creation (Spoon). I did some research and found that the JDT compiler allows to attach a CompilationProgress. For the model creation, I would suggest to fire a progress event for each compilation unit.

Wrapping JDT's CompilationProgress class with a custom progress listener should be straightforward.

What do you think?

[monperrus]

It makes sense.