Api query branch pagination update

This should pretty much solve #85. Please do not merge yet, because we still have to figure out permissions for Submissions' index. Feedback/review would be appreciated.
You should set the pagination limit thing to be less than the number of instances you add. Can you add some tests for this?

I think there should be a way to set the pagination limit in the request. If that's too hard to add right now, that's fine; just create an issue.