generic launcher

Hello,

I'm developing a Henshin Concurrent Engine for gemoc with @szschaler and I've noticed that I had to copy a lot of code into my launcher. It seems that there's no generic launcher so I was wondering if it would be possible add one in the next versions to reduce the code redundancy.

[Your launcher](https://github.com/eclipse/gemoc-studio-execution-moccml/blob/master/ccsljava_engine/plugins/org.eclipse.gemoc.execution.concurrent.ccsljavaengine.ui/src/main/java/org/eclipse/gemoc/execution/concurrent/ccsljavaengine/ui/launcher/Launcher.java)

[Our launcher](https://github.com/szschaler/henshin_xdsmls/blob/master/uk.ac.kcl.inf.modelling.xdsml.gemoc_henshin/src/uk/ac/kcl/inf/modelling/xdsml/gemoc_henshin/engine/ui/launcher/HenshinConcurrentEngineLauncher.xtend)

Thank you,
Kinga