special resource descriptions provider (needed to address DS-7312)

Hi - we need this to address http://rd.oams.com/browse/DS-7312, plz...

PS: The inclusion of https://github.com/temenostech/IRIS/pull/88 here is because I branched it off wrong (that FB instead of master), not because one requires the other (they are technically totally unrelated). As I'm lazy, and you're likely to treat both together anyway, I won't redo it.