- Fixed determining package status of directory to go through the UTI tr...

...ee.

The old code was a bit simplistic and results in certain folders being treated as packages when they shouldn't. This new method actually goes through the UTI tree looking for the package type which should be far more accurate. Note, though, that getting the UTI declaration is a bit expensive so I added a static cache. If you want, you can stick this as an ivar though this info should be the same system-wide.