Reworked translation system:
tr.addLanguage()
to tr.addTranslations()
tr.deleteTranslations()
to delete translations for the given or active languagetr.hasKey()
to check if the translation with the given key exists for the given or active languagetr.addTransform()
to add a transform function for all languages that can dynamically modify translationstr.deleteTransform()
to delete a previously registered transform function