attribute filter RuleReference ?

[Tom Zeller]

>>Should we remove RuleReference from the attribute filter schema or
>>leave RuleReference unimplemented as in IdPv2 or should we implement
>>it for IdPv3 ?
>
> I think it's down to time to implement. If it were a couple of hours time
> to get it done, I would say just do it. If it's a day or more work, I
> would defer it as an open item and at ship time assess and have either
> closed it or remove the elements from the schema.

FWIW, relevant issue is https://issues.shibboleth.net/jira/browse/SC-175