Updated User and Class daos and tests.
Merge pull request #14 from jwien001/master

More Dao work
Work on ProblemSetDao. Cleaned up all daos.
Merge pull request #15 from rlobo3/master

Controller calls signin
Merge pull request #16 from jwien001/master

Updated ProblemSet dao and tests.
Updated problem dao and tests.
Added more prereq methods.
Updated Login method to return the user's info.
Merge pull request #17 from jwien001/master

More Dao work and update to Login method.