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...
I see no other way to determine toolchain element details (i.e. both name/version)... We can rely on a toolchain module, since it might not be there yet (and extracting version info from there would be messier too).