Localization

We need a localization guide.
- http://developer.android.com/guide/topics/resources/localization.html
- https://developer.android.com/distribute/tools/localization-checklist.html
- http://android-developers.blogspot.fr/2013/03/native-rtl-support-in-android-42.html
