gcd: convert most of loops to submit work in 32 item size batches. MBP6,2 (2 core 4 thread), catmark_car Lv3: 6.9ms CPU, 5.2ms GCD; Lv4: 31.2ms CPU, 22.ms GCD
gcd: convert most of loops to submit work in 32 item size batches.
MBP6,2 (2 core 4 thread), catmark_car Lv3: 6.9ms CPU, 5.2ms GCD; Lv4: 31.2ms CPU, 22.ms GCD

takahito-tejima/OpenSubdiv,shengfuintel/OpenSubdiv,takahito-tejima/OpenSubdiv,jcowles/OpenSubdiv,c64kernal/OpenSubdiv,takahito-tejima/OpenSubdiv-exp,xldeveloper/OpenSubdiv,takahito-tejima/OpenSubdiv-exp,lookup1980/OpenSubdiv,xldeveloper/OpenSubdiv,takahito-tejima/OpenSubdiv,shengfuintel/OpenSubdiv,anshuarya/OpenSubdiv,nyotis/OpenSubdiv,anshuarya/OpenSubdiv,shengfuintel/OpenSubdiv,jcowles/OpenSubdiv,lookup1980/OpenSubdiv,nyotis/OpenSubdiv,anshuarya/OpenSubdiv,poljere/OpenSubdiv,c64kernal/OpenSubdiv,takahito-tejima/OpenSubdiv-exp,jcowles/OpenSubdiv,poljere/OpenSubdiv,lookup1980/OpenSubdiv,c64kernal/OpenSubdiv,nyotis/OpenSubdiv,takahito-tejima/OpenSubdiv-exp,poljere/OpenSubdiv,xldeveloper/OpenSubdiv