Remove ColorTransfer, add optional OpenColorIO support about oiio HOT 2 CLOSED

My opinion is that OIIO should have a color conversion utility function (not unlike convert_image -- in the global namespace) that takes a pointer to a buffer and strides, and from/to color space names. If OCIO is found at build time, then this function is just a thin and convenient wrapper around the handfull of OCIO calls. If OCIO is not found, perhaps the function can default to implementing just the most basic conversions (linear <-> sRGB, and gamma, perhaps) and ignoring all else. That way, some core functionality is preserved even when no OCIO is found, but not anything complicated, we rely on OCIO when it is found, and in either case there's a uniform and simple wrapper that we expose to OIIO client apps that keep them from having to know whether OCIO is truly available or how to call to it.

from oiio.

Closing, this has been in since 1.0.

from oiio.