Adding basic persistence

 - pom.xml has been expanded with the failsafe plugin for integration
   tests
 - All model entities updated to add persistence annotations
 - DBUnit helper classes have been introduced
 - Simple data export class added for convenience
 - Added logging support
Adding persistence and integration test

 - Maven support integration test
 - Use Spring test support for integration test
 - logging is enabled
 - Optimistic locking in hibernate enabled
 - Model classes enriched