Added created and last modified timestamps to the group_app model.
Also edited the templates to show some extra information. The review template has the names for the new properties hard coded because the auto_add and auto_add_now datetimeproperties don't show up in the fields of the entity.
Patch by: Lennard de Rijk
# Please sort this file in alphabetical order by last (given) name.
# Please only include one name per line. If an (optional) email address is
# included, it must be RFC 2821 compliant (properly quoted, escaped, etc.).
# Lines beginning with # can be stripped from the file, as can blank lines.
"Mario Ferraro" <fadinlight@gmail.com>
"Todd Larsen" <tlarsen@google.com>
"Chen Lunpeng" <forever.clp@gmail.com>
"Sverre Rabbelier" <sverre@rabbelier.nl>
"Lennard de Rijk" <ljvderijk@gmail.com>
"Pawel Solyga" <pawel.solyga@gmail.com>