support for hierarchical module naming schemes

@geimer: this should fix the problem that's blocking you right now

I might need to figure out one more thing w.r.t. the devel module name before this really works for you, I'm looking into that...
In fact, I *need* to move these into a namespace that is dynamically extensible, otherwise building-EasyBuild-with-EasyBuild is broken (because we added `hierarchical_mns.py` which require these `det_toolchain` functions, which are only available now (I won't go into the full details, but that's the problem)

The issue is that these `det_toolchain` functions require `easyconfig` functionality though...