Add approximate ray differentials for blurry BSDFs (trac#69)
Add approximate ray differentials for blurry BSDFs (trac#69)

git-svn-id: 93cebb81a0f5cc00f31a7ad40d16024532691b70@404 a3683778-fedd-11de-87c3-653bb6514e15

mcanthony/OpenShadingLanguage,aconty/OpenShadingLanguage,imageworks/OpenShadingLanguage,juvenal/OpenShadingLanguage,fpsunflower/OpenShadingLanguage,rlmh/OpenShadingLanguage,Anteru/OpenShadingLanguage,imageworks/OpenShadingLanguage,juvenal/OpenShadingLanguage,imageworks/OpenShadingLanguage,lgritz/OpenShadingLanguage,rlmh/OpenShadingLanguage,mcanthony/OpenShadingLanguage,aconty/OpenShadingLanguage,amartinez-cg/OpenShadingLanguage,mcanthony/OpenShadingLanguage,Anteru/OpenShadingLanguage,johnhaddon/OpenShadingLanguage,brechtvl/OpenShadingLanguage,yaroslav-tarasov/OpenShadingLanguage,brechtvl/OpenShadingLanguage,Anteru/OpenShadingLanguage,lgritz/OpenShadingLanguage,mcanthony/OpenShadingLanguage,Anteru/OpenShadingLanguage,fpsunflower/OpenShadingLanguage,rlmh/OpenShadingLanguage,amartinez-cg/OpenShadingLanguage,aconty/OpenShadingLanguage,johnhaddon/OpenShadingLanguage,johnhaddon/OpenShadingLanguage,svenstaro/OpenShadingLanguage,aconty/OpenShadingLanguage,gzorin/OpenShadingLanguage,brechtvl/OpenShadingLanguage,rlmh/OpenShadingLanguage,yaroslav-tarasov/OpenShadingLanguage,gzorin/OpenShadingLanguage,fpsunflower/OpenShadingLanguage,sjparker/OpenShadingLanguage,sjparker/OpenShadingLanguage,aconty/OpenShadingLanguage,brechtvl/OpenShadingLanguage,lgritz/OpenShadingLanguage,juvenal/OpenShadingLanguage,fpsunflower/OpenShadingLanguage,johnhaddon/OpenShadingLanguage,svenstaro/OpenShadingLanguage,gzorin/OpenShadingLanguage,gzorin/OpenShadingLanguage,yaroslav-tarasov/OpenShadingLanguage,svenstaro/OpenShadingLanguage,lgritz/OpenShadingLanguage,juvenal/OpenShadingLanguage,amartinez-cg/OpenShadingLanguage,sjparker/OpenShadingLanguage,imageworks/OpenShadingLanguage,gzorin/OpenShadingLanguage,sjparker/OpenShadingLanguage,lgritz/OpenShadingLanguage,yaroslav-tarasov/OpenShadingLanguage,imageworks/OpenShadingLanguage,amartinez-cg/OpenShadingLanguage,amartinez-cg/OpenShadingLanguage,svenstaro/OpenShadingLanguage,brechtvl/OpenShadingLanguage