fixes to ao16 accumulation code
fixes to ao16 accumulation code

favreau/OSPRay,favreau/OSPRay,ospray/OSPRay,ospray/OSPRay,MengjiaoH/ospray,Twinklebear/OSPRay,MengjiaoH/ospray,MengjiaoH/ospray,Twinklebear/OSPRay,wilsonCernWq/ospray,ospray/OSPRay,favreau/OSPRay,wilsonCernWq/ospray,MengjiaoH/ospray,MengjiaoH/ospray,Twinklebear/OSPRay,ospray/OSPRay,favreau/OSPRay,Twinklebear/OSPRay,wilsonCernWq/ospray