Merge pull request #39 from jwien001/master

Added a ProblemSet view.
Merge pull request #40 from jwien001/master

Implemented CRUDing Problem Set prerequisites
Merge pull request #41 from jwien001/master

Removed need for persistent class storage in the ProblemSet edit page.
Merge pull request #42 from jwien001/master

Added a Problem view with field editing working.
Merge pull request #43 from jwien001/master

Added enhanced editors for the appropriate Problem fields.
added methods for class in Core
New changes and recommit
Merge pull request #46 from rlobo3/master

Changes for Class stuff
Implemented add/remove Problem to/from Sets.

This functionality can be accessed via the Problem Set list at the
bottom of the Problem view page.