Introduction of a new Transaction API that is more consistent with the style
of Spring's transaction managment. The existing Transaction class was renamed
to TransactionLegacy. All of the non-DAO code in the management server has been
updated to use the new Transaction API.
User should be able to delete/archive alerts and events by selecting a time period or by
choosing the alerts and events older than a date. Added the ability to choose a time period
too.