Reachability ideas

[pettermahlen]

We could probably improve the reachability logic a bit.

• If a class is referenced somewhere, we should visit the static initializer method
• If a class is instantiated somewhere, we should visit all non-static methods (because we can't really know when they're going to be invoked because of external interfaces and inheritance)
• Static methods should only be visited when they're actually called.

[pettermahlen]

This (and maybe more) would probably be solved by proguard #9. That's not necessarily the best solution, but one solution at least.