switched from calling the managed to the manual db transaction start method. refs #3430
updated doc block.
removed unused method markAlertAsDispatched()
fixed typo.
removed transaction handling from method saveAuditEvent. refs #3430
removed transaction handling from method addOrUpdateAlert(). refs #3430
wrapped calls to addOrUpdateAlert() with transaction handling code as applicable. refs 3430
wrapped calls to saveAuditEvent() with transaction handling code. refs #3430
added transaction handling for saving change alerts in method disassociateLearningMaterial()
added transaction handling for call to method markAlertsAsDispatched(). refs #3430
Merge pull request #124 from ucsflibtopfstedt/bug3430

refactored db transaction handling code