Removed link to incomplete 'Textures' doc.
Removed link to incomplete 'Textures' doc.

Removed the link to the 'Textures' document because it is incomplete.
Still keep the texture document (in the tree and in the CMakeLists.txt to one day revive.

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