Userrights work. Changes:

Userrights work. Changes:
* Behaviour of $wgAddGroups and $wgRemoveGroups changed. New behaviour:
* * Granting the userrights privilege allows arbitrary changing of rights.
* * Without the userrights privilege, a user will be able to add and/or remove the groups specified in $wgAddGroups and $wgRemoveGroups for any groups they are in.
* Merge interwiki code from the MakeSysop extension into core.
* New permission userrights-interwiki for changing user rights on foreign wikis.