Fix localization in OS X

Prior to this fix, the application menu in OS X would ignore the current localization setting and default to english.

The fix consists of two parts:

1. Declare support for each language by including an empty `.lproj` directory inside the Resources folder of the app bundle.
2. Make sure that OS X honors the user specified language by writing its value in the `AppleLanguages` key of the application defaults file.

Note that the `ant` code is a bit funny, since it requires `ant-contrib` and is even longer than just copying the mkdir line for each supported language, but it does have the benefit that translators don't need to change yet another piece of code. It just reads each key from the `languages.txt` file.