standardize format of json responses

[nathanallen]

Perhaps following http://jsonapi.org/format/#document-structure

ping @tgaff

[tgaff]

It's a good idea and of course I think we should do our best to use standards.
I'm not sure this's really a standard yet, more like a proposal. (Hit 1.0 in May of last year) It also is mostly backed just by ember guys at this point (couple of big names though). I did a quick search for this and angular and it's not clear whether the Angular community is getting on board here or not.

It's also maybe more complexity than our students need; especially this being their first back-end lab. Maybe we can use it or a simplified version for a later lab though.