Add new _parler_meta attribute, that will replace _translations_model / _translations_field
Add new _parler_meta attribute, that will replace _translations_model / _translations_field

It's still compatible with the existing code that may have read the
internal _translations_model attribute

ellmetha/django-parler,HiddenData/django-parler,skirsdeda/django-parler,django-parler/django-parler,ellmetha/django-parler,defivelo/django-parler,imposeren/django-parler,edoburu/django-parler,zhangguiyu/django-parler,jrief/django-parler,jrief/django-parler,django-parler/django-parler,skirsdeda/django-parler,HiddenData/django-parler,edoburu/django-parler,zhangguiyu/django-parler,imposeren/django-parler,defivelo/django-parler