WIP: Feature/update feedback on giving feedback
Depends on !116 (as I am too lazy to bother setting up the tests again).
WIP (as started by @pimotte) to make sure the feedback API call is used to update the rubric as items are clicked. This ensures that (without the full exam update introduced by !100 (merged) and removed by !116) you still see new rubric items created by another grader, without having to hit F5.
I think it would be good to add some tests before merging (hence the WIP), but it should probably be good to go as is, in terms of functionality.