CDL Color Transform Effect

[reinecke]

There is a continuum of color management that can potentially be included in OTIO (see #1805). Based on discussions in that thread and #1793 we feel like we know enough to implement a CDL effect schema.

The Schema should be:

{
  "OTIO_SCHEMA": "CDLEffect.1",
  "metadata": {},
  "offset": [
    0.0,
    0.0,
    0.01
  ],
  "power": [
    0.5,
    0.5,
    0.51
  ],
  "slope": [
    1.0,
    1.0,
    1.0
  ],
  "saturation": 0.0,
  "process_space": "ACEScct"
}

This would be a subclass of the otio Effect schema.

By practice - process_space should be a name from the OCIO studio config.