Need to ifdef the CUDA registration (we need a better mechanism...)
Need to ifdef the CUDA registration (we need a better mechanism...)

Closes #21.

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