Preparing the code to support 'order_by()' chaining after '.all()' and '.filter()' in mixins.
Add '.destroy()' to the GraphMixin and the Neo4j backend
Not sure why the code was like it was. I enabled support again for reflexive but directed relationships, even when implies a reduntant formset when the schema have them.
Ref trello#343. For reflexive relationshps, show only as target those nodes are not itself
Merge