Add additional LDAP search

Hello,

I added a feature to the LDAP part. Now you can specify an additional LDAP search string in the ccnet.conf file. With this you can search for group members.

i.E (in ccnet.conf [LDAP] section):
To read direct members of a group use:
SEARCH = memberof=CN=YourGroup,OU=Users,DC=YourDomain,DC=com

To do a recursive (usersA in GroupA, GroupA in YourGroup) search on ActiveDirectory (don't know of OpenLDAP):
SEARCH = memberof:1.2.840.113556.1.4.1941:=CN=YourGroup,OU=Users,DC=YourDomain,DC=com


Note that you have to enable the memberof feature on OpenLDAP.