Added code to explicitly roll back a failed commit

If a commit fails it throws an exception but doesn't roll back the transaction.  Instead it leaves it with an error on the connection, which
causes the next commit to fail and rollback.  Instead you should catch the exception, roll-back, and rethrow
Merge branch 'master' of github.com:ucam-cl-dtg/urop-2013-dashboard
Set supervision-api to use SNAPSHOT version
Removed dependency on resteasy-multipart and replaced it with dependency on javax.mail

I think javax.mail provides everything that this project needs without needing to pull in all of multipart