Django-adldap-sync

* Complete overhaul of the system. Renamed to django-adldap-sync
* Added Group Membership Synchronization
* Added Incremental Synchronization
* Added support for failover ldap servers
* Added a simple way to populate User Profiles
* Support for importing thumbnailPhoto to ImageField
* Added support for ignoring users on import
* Created a model for storing last update time, and statistics

* Fix error when synchronizing groups
* Add setting to retrieve additional LDAP attributes
* Pass attributes to user callback functions
* Add example callback for disabling users with AD userAccountControl

* Fix packaging errors

* Add a setting to override the username field
* Add handling of removed users
* Implement callbacks for added/changed and removed users

* Handle DataError exception when syncing long names (thanks tomrenn!)
* Change Celery task to use shared_task decorator

* Fix exception with AD internal referrals