localized_fieldnames_rev is no longer available, but should be replaceable by field.translated_field.
Manage translation fields inherited from concrete supermodels in admin.
Allow TranslationAdmin to be used with unregistered models.
Adapt update_translation_fields command to bigger registry.
Small cleanup in FieldsAggregationMetaClass.
Ensure that a base class is not registered after a descendant.
Update the debug message.
Merge branch 'feature/complex-inheritance' into develop

Conflicts:
	modeltranslation/admin.py
	modeltranslation/management/commands/update_translation_fields.py