* Add auth_ad_(group|user)_filter options
* use global
* Fix some AD annoyances
Use the power of the LDAP filter to minimize the number of queries and
hopefully help performance in get_userlist, change semantics of
auth_ad_(user|group)_filter in $config to be anded with
samaccountname=USERNAME.
* remove unused variable
* update documentation
* Update Authentication.md
* Updated to remove passwords from sessions
* Remove users sessions when user deleted
* Updated when cookies are set
* Updated setcookies to always contain a value
* Added destroy_cookies() to remove users cookies on failed login
* Removed debug line
* Fixed graph issues