Added integration_tests app to example project

- added integration_tests to tox
Added badges
Lot faster tests
Added coveralls support and badge
Added missing sha1 hasher
Bumped dev version
Cache content types for classes.
Change get_objects_for_user so it creates much more efficient queries when not using groups.
Change get_objects_for_user so it creates much more efficient queries when not using groups.
Whoops.
Add test to give get_objects_for_user 100% coverage again.
Merge faster_get_objects_for_user. Fix conflict.
Support usage without anonymous users

With some custom models, creating users may be complicated; reasonable
defaults may not exist for some fields, and special-casing a sentinel user
elsewhere in views code separately from Django's provided AnonymousUser may
be unpalatable.

For these situations this commit adds the ability to disable anonymous user
support entirely; any permissions check against such a user will always
return False. No user is created when "syncdb" is run.

To disable anonymous user support in your site, set ANONYMOUS_USER_ID to
"None" in settings.py.

An unset ANONYMOUS_USER_ID will still cause an error.
Document ANONYMOUS_USER_ID=None in configuration.rst
Added Python 3.3 to be checked by travis. Fixes #149
remove_perm does not fire post_delete signal is now documented. Fixes #128
GuardedModelAdmin patch for supporting USERNAME_FIELD
error message fixed, tests run when "testsettings.py" is used
Fixed flakes
Simplified migrations test