Allow serveResource to fetch employee at login

EV-203

The serveResource was assuming that the loggedOnUser was cached in
session. When this wasn't the case, it was throwing an exception
because the hibernate session was started too late in the method.
Added unit test to check that the employee object is fetched properly
by EvalsPortlet.serveResource.
Merge pull request #54 from osu-mist/feature/EV-203-serve-resource-hibernate

Allow serveResource to fetch employee at login