Unable to add localizations/subdirectories

[sbeitzel]

The pass documentation from Apple says that localizable resources should be stored in subdirectories, but when one adds a file with a custom name such as, "en.lproj/pass.strings" the operation fails, since the "en.lproj" subdirectory doesn't exist.

[aydenp]

I merged #4, but going to keep this open since it still appears to affect addFile(named:,from:)

[aydenp]

#12 tracks removing the method which doesn't support subdirectories