Locale definition
Documentation of the keys:
- 'name' : The locale name displayed to the user (keep short).
- 'charset' : Character set of the locale's messages files.
- 'datefmt' : The date format for this language. See date_i18n().
- 'timefmt' : The time format for this language. See date_i18n().
- 'startofweek': Start of week for this locale. 0 means Sunday, 1 Monday etc.