Dependency Explorer: check for duplicated paths outside of haxelib repo

[Gama11]

If there's a library that's shown as a dependency, we don't show classpaths that are just subdirectories of that library separately as well. This happens with OpenFL for instance, which has an additional "externs" classpath.

However, this logic currently doesn't account for libraries located outside of the haxelib repo (thanks @jgranick for reporting):

There should only be 4 entries (which is the case with my setup):