trivial change
whitespace
sync tests/settings with okupy/settings/*
Move tests.tests.example_directory to tests.settings.DIRECTORY
Add LDAPUser model, from django-ldapdb

It is in very early stage, plus it has many hardcoded things, but it provides
the API we want to get LDAP accounts as python objects.

TODO list regarding LDAPUser and django-ldapdb can be found at:
https://github.com/gentoo/identity.gentoo.org/wiki/TODO_tampakrap#django-ldapdb

Example:
>>> alice = LDAPUser.objects.get(username='alice')
>>> developers = LDAPUser.objects.filter(ACL__contains='dev.group')

PS Since it is in early stage, and the final form of it is not fully defined
yet, I'm skipping the tests for now till we have a final design