Fix admin inlines for subclasses doing their own fields manipulations (e.g. through get_fieldsets).
Merge branch 'feature/dynamic-inlines-fieldsets' into develop
Merge branch 'feature/dynamic-inlines-fieldsets' into feature/modeltranslation-integration
Modeltranslation now supports tabs in admin inlines.
Merge branch 'feature/modeltranslation-integration' into develop