HOTFIX: Added an admin filter to show graphs without annotations. Overridden Image and Annotation delete function to delete associated graphs. Note that some graphs may survive when a bulk delete is done through the admin as Django doesnt call delete. Might be improved by using signals but attempt was not concluant.
HOTFIX: better fix for the problem of orphan graphs. JIRA DIGIPAL-523. This will work even for bulk delete of image or annotation records.