Improved our tests so that they don't raise an error if setuptools isn't...

Improved our tests so that they don't raise an error if setuptools isn't installed, hence ridding the test suite of all dependencies. Also updated docs.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@7751 bcc190cf-cafb-0310-a4f2-bffc1f526a37