Use github URI in setup.py.

So far, there's nothing on identity.gentoo.org and the URI in setup.py
should point to a kind of homepage where sources, bug tracker
and downloads are available.
Use @property decorator where applicable.
Replace deprecated .iteritems() with .items().
Replace render_to_response() with simpler render().
Use django.shortcuts.redirect().
Use a new branch from the forked django-auth-ldap
Merge pull request #1 from mgorny/code-cleanup

Code cleanup
Merge branch 'master' of github.com:gentoo/identity.gentoo.org