Added note about the addition of the django.contrib.staticfiles app. Thanks to...

Added note about the addition of the django.contrib.staticfiles app. Thanks to Florian Apolloner for reminding me about it and providing a patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@14532 bcc190cf-cafb-0310-a4f2-bffc1f526a37