Fixed #1321 -- Made DJANGO_SETTINGS_MODULE optional. You can now call django.conf.settings.configure() to set settings manually if you don't have a settings module. Thanks, Malcolm Tredinnick, Luke Plant, Fredrik Lundh

git-svn-id: http://code.djangoproject.com/svn/django/trunk@2927 bcc190cf-cafb-0310-a4f2-bffc1f526a37