Commit
f4d65f1c52d7b9f9be1779bdfefff8a3eef189c4
by jacasanovatsk58-59 Adds the attribute cancelled to Event
Modifies Event to include the attribute cancelled. Modifies EventEJB to
support the new attribute and includes the new exception
EventIsCancelledException (now an User can't join a cancelled Event and
a cancelled Event will not appear in a search). Modifies Tests to
support the new attribute. Modifies Datasets to support the new
attribute. Modifies DB (sql) to support the new attribute.