Bug 818999 - Update ar, fr, zh-TW as of December 6

This will fix the issue from [bug 818015](https://bugzilla.mozilla.org/show_bug.cgi?id=818015) and probably many others.

This is not required to ship the final product.  The purpose of this patch is to make it easier for developers to get started just by cloning mozilla-b2g/gaia.  We want them to start with a somewhat-up-to-date set of locales to test localizability and internationalization.

The real infrastructure to build multilocale Gaia is being tracked in [bug 766962](https://bugzilla.mozilla.org/show_bug.cgi?id=766962).