Fixes #13

This adds a post-process step which automatically adds unambiguous imports,
removes unused imports and sorts the import list (formatting matches standard
IntelliJ settings).
This will preserve line count across versions at all cost.

Java only for now because it's a lot more tricky with Kotlin and we don't yet
use Kotlin ourselves (and won't be preprocessing it in the future either).

Used to only compare the arguments, nether the class nor the qualifier (the
outer class instance for inner classes constructor calls).