Filter string can be unicode.
Django 1.6 fix.

module_name was renamed to model_name in django.db.models.options, so we
do the same thing too, in order to maintain compatability.
Remove SG: prefix from groups.
Version 0.2.10.
Fix order of parameters.
Check LDAP_URL is defined before trying to use it.

Make it possible to have 0 LDAP servers defined.
Version 0.2.11-1.