Fixed #11745 -- Grouped commands by application in the output of `manage.py...

Fixed #11745 -- Grouped commands by application in the output of `manage.py help`. Made 'version' consistent with 'help' while I was in the area, and added tests. Thanks Jannis for the feedback and review.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@17462 bcc190cf-cafb-0310-a4f2-bffc1f526a37