Added support for Django 2.0; minor bugs and regressions fixed. Adds abstract base classes for Resources - see documentation. Adds optimization for getting multiple objects by id in a single query.
- Add explicit error when ModelResource lacks object_class and queryset
- Update urls to slumber and biplist
- Alter length of URL field in ApiAccess model (to open-ended TextField)
- Fix Advanced Filtering example in documentation (with unit test)
- Fix regression in ToManyField.dehydrate with a null value. (#1544)