REST adapter limits

@paulyoder I meant to add: to be totally honest though, we still have issues with ED in a (fairly) big app. My impression is ED works well in fairly simple cases, but when you need to deal with complex relationships graphs, lots of objects, and not so consistent back-ends, there are problems (for instance: Am I lost or is Ember-data still problematic?). Or, I should say: WE struggle to make it work (it could well be that it’s just us). So if we had to do it again, I am not totally sure we would use ED.