add clang arch job, add centos6/7 jobs
add clang arch job, add centos6/7 jobs

MengjiaoH/ospray,MengjiaoH/ospray,ospray/OSPRay,MengjiaoH/ospray,ospray/OSPRay,MengjiaoH/ospray,ospray/OSPRay,MengjiaoH/ospray,wilsonCernWq/ospray,wilsonCernWq/ospray,wilsonCernWq/ospray,ospray/OSPRay