Bugfix: Parser would not reach EOF when errors found
Bugfix: Empty strings were not parsed correctly
Bugfix: Empty strings were not output correctly
Bugfix: Java target builder expected single-element paths as input-dir

New: Add _locale static member to generated classes containing an array
     of the names of generated locales

Change: Do not add the whole Locale to LocaleInterfaceError for better
        readability (custom Show instance for LocaleError is coming soon
        anyway)
Improved messages
Added check for conflicting signatures
Refactored Main