added availableLanguages property with all languages available for translation;
removed underscore from beginning of the name of all private properties;
renamed "fbModel" private property to a more suggestive "fallbackModel" name;
renamed "language" private property to a more suggestive "currentLanguage" name;
adding saving of all translations for all the languages on owner save;
made sure loadTranslationModel method doesn't query the database for data the object already has;