Change testshade so that it can shade at pixel centers, not just at grid points
Change testshade so that it can shade at pixel centers, not just at grid points

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