#17: added basic creation function for organization entities

Task-Url: https://github.com/mgatz/sunrise/issues/issue/17
#17: added basic validation rules to the DefaultOrganizationEntity
implementiation

Task-Url: https://github.com/mgatz/sunrise/issues/issue/17
#17: added beans needed to enable validation using JSR 303

Task-Url: https://github.com/mgatz/sunrise/issues/issue/17