diffuse part of disney's brdf.
added disney diffuse brfd.
Added the missing params to disney's brdf.
More refactor work.
Fixes and optimizations for Disney diffuse.
MDF interface experiments.
stateless MDFs prototype.
stateless MDFs prototype.
Moving to a more classic polymorphic style.
More mdf recaftor work.
Material class refactor, added disney material class for later.
More disney tests
Merge branch 'stateless_mdfs' into OSL_microfacet_update
microfacet refactors for OSL.
More MDF work.
Merge branch 'master' into OSL_microfacet_update
Many changes to MDF refactor classes.
More MDF refactor work.
Merge remote-tracking branch 'upstream/master' into OSL_microfacet_update
Small refactor to QMC code. Expose the OSL MDF BRDF in studio.