Only register before_filter set_user_language if it has not been registered yet, guaranteeing the filter retains its original position in the callback chain. Also, make sure the before_filter globalize_fallbacks is run before any other i18n filters.
Merge pull request #432 from jschwertfeger/fix/duplicate_set_user_language_filter_registration

Only register before_filter set_user_language if it has not been registe...