Added support for OpenColorIO displays with the new --ociodisplay flag.

The new --ociodisplay flag applies color transforms from an OCIO
display/view combination. Optional keywords are "from" (source colorspace),
"looks" (optional looks overrides, supports empty string to disable looks),
and the same "key" and "value" keywords as --ociolook.
Switched to using ImageBufAlgo::ociodisplay, added it to Python API
- added ImageBufAlgo::ociodisplay to wrap applying an OCIO display transform ColorProcessor
- changed oiiotool to use ImageBufAlgo::ociodisplay instead of creating the ColorProcessor and applying it with ImageBufAlgo::colorconvert
- added ociodisplay to Python API
ociodisplay docs
Merge branch 'ociodisplay'