##Problem Render
This needs to exist in both the webwork server and in PG.
The webwork server will request rendering and check answers using PG's API
The reason for the redundancy is that PG shouldn't care about state when checking answers whereas WeBWorK needs to record attempts etc.
###get rendered (id, path, code)
GET /problem
body contains id, path, code ###check answer (id, path, code)
POST /problem/check
body contains id, path, code and answer ###create (code?)
POST /problem/create
body contains code (maybe path?)