LoginAction now denies people trying to log in as a User if that User is
already logged in under a different client.
Implemented multi-right users - a User can now be an Administrator, a
Judge, a Competitor and even an AuxServer all at the same time.
Added Network javadocs.
Added SUBMISSION_RECEIVED and SUBMISSION_GRADED events.
Merge branch 'dev' into uinogui
Submission WIP