Ensure that ModelSerializer fields are in same order than in DRF#1182

sliverc merged 4 commits intodjango-json-api:maindjango-json-api/django-rest-framework-json-api:mainfrom

antoineauger:fix/sort-field-namesantoineauger/django-rest-framework-json-api:fix/sort-field-namesCopy head branch name to clipboard