added dPdu and dPdv to the list of supported predefined primvars in the SX renderer
added dPdu and dPdv to the list of supported predefined primvars in the SX renderer
tectronics/cortex-vfx,AlanZatarain/cortex-vfx,Alwnikrotikz/cortex-vfx,tectronics/cortex-vfx,Alwnikrotikz/cortex-vfx,AlanZatarain/cortex-vfx,Alwnikrotikz/cortex-vfx,AlanZatarain/cortex-vfx,tectronics/cortex-vfx