no longer using embree::thread_t - replaced with std::thread class
no longer using embree::thread_t - replaced with std::thread class

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