Include primitive's geometry normal in Intersection

[qhaas]

Embree (2.8.x at least) includes the intersected primitive's (facet's) unnormalized geometry normal (Ng) in its intersection return data. While trying to port some code from Embree to RadeonRays, I noticed RadeonRays doesn't have a way to retrieve this value and thus I have to manually calculate it. It would be nice if there was a way to retrieve this data from the RadeonRays API. If not returned by Intersection, then maybe a RadeonRays API query to retrieve it by shapeid / primid.

[devshgraphicsprogramming]

@qhaas how would you propose to change the API of Radeon Rays for this?