fyi : idp-attribute-filter-api refactoring

[Tom Zeller]

Notifying anyone interested that idp-attribute-filter-api has been refactored.

MatchFunctor is now Matcher and evaluatePolicyRule() is now matches().

In package names and classes, "filtering" has been replaced with
"filter", so that the AttributeFilteringEngine is now just
AttributeFilter.

There probably should be a JIRA issue and some more process
surrounding API refactoring, but this will need to suffice for now.

Feedback is welcome.