Versión en Español para Mac

It turns out that localized resources for Inkscape on OS X mainly just need an extra directory added to the application bundle. The directory does not need any contents.

To make the released Inkscape show up in Spanish, find the "Inkscape" application and right-click on it.
Select "Show Package Contents"
Go into the "Contents" folder
Go into the "Resources" folder
Create a new folder
Name that folder "Spanish.jproj"

The next time you launch Inkscape and have Spanish set as a preferred system language, Inkscape should come up with Spanish messages.

And to disable Spanish, navigate into the application by using "Show Package Contents"
Go into the "Contents" folder
Go into the "Resources" folder
Go into the "locale" folder
find the folder named "es" and rename it to something else, like "disable_es"

If someone who has been building Inkscape.app versions for OS X could test this, that would be good. It should enable the resulting Inkscape 'binary' to launch with a few different languages (based on system preference in "International") including French, German, Spanish, etc.

The localisation was working for me before already, so I can't really test that. But there is no harm in adding those dirs so I committed the patch at rev 21367.