Fixed #4879 -- Added 'created' arg to post_save signal. This is True is a new object is created. Patch from George Vilches.

Fully backwards compatible, because signal receivers do not have to be able to accept all the arguments (thankyou, robust_apply()).


git-svn-id: http://code.djangoproject.com/svn/django/trunk@6269 bcc190cf-cafb-0310-a4f2-bffc1f526a37