Added support for group auth, 2 new settings:
- LDAPAUTH_GROUP_ATTR
- LDAPAUTH_GROUP_REQ
If they're not set don't check group membership.
Added support for using a privileged account to do the user search. 2 new settings:
- LDAPAUTH_SEARCH_USER
- LDAPAUTH_SEARCH_PASS
Limited returned attributes to only the ones we need.