- Added localization

Hey, Jon,

Love your category, and I think it will be very useful, but I do a lot of internationalized apps where you can't just add an "s" at the end, so I went ahead and localized your category for you. It defaults to English, so you shouldn't see any change there. 

Internally, the biggest difference is that you have to separate out the singular from the plural. In Spanish, for instance the word for month is "mes" and months is "meses", so it's an "es" addition instead of just an "s". Now, if someone wants to user your category to build international apps, they can simply provide the localized string for both. Please run it through any testing scripts you may have just to verify that it works, but everything should hold.

I'll let you update the readme for this if you decide you want it.

Thanks,

-Matt