FIX: client's translation overrides were not working when the current locale was missing a key
FIX: ExtraLocalesController.show was not properly handling multiple translations
FIX: JsLocaleHelper#output_locale was not properly handling multiple translations
FIX: ExtraLocalesController.show's spec which was randomly failing
FIX: JsLocaleHelper#output_locale was muting cached translations hashes
REFACTOR: move 'enableVerboseLocalization' to the 'localization' initializer
REFACTOR: remove unused I18n.js methods (getFallbacks, localize, parseDate, toTime, strftime, toCurrency, toPercentage)
REFACTOR: remove all I18n.pluralizationRules and instead use MessageFormat's pluralization rules
TEST: add tests for localization initializer
TEST: add tests for I18n.js
Persian does not distinguish between the singular and plural forms
of nouns in the same way as English does. For numbered elements,
always return the 'other' key from the translation file.
