Dao test refactoring

The ApplicationDaoTest had some methods to test if the modified field is working correctly. As this field is being updated in the GenericHibernateDao, this behaviour should be tested in a test for the GenericHibernateDao (and not in the ApplicationDaoTest). For this reason a new test "GenericHibnernateDaoTest" has been created (to have some kind of semantic separation). As GenericHibernateDao is an abstract class, we cannot instantiate it to test this. Hence the ApplicationDao (as an simple extension of the GenericHibernateDao) is used in the new test.