agx module development

[Peyton_Creery]

I think a lot of the reasoning and history can be found here

There are several discussions happening around AgX tonemapping and I wanted to see what it was all about.

• AgX, Color Shifts, and The Notorious 6 in Darktable - Avid Andrew
• OCIO, Display Transforms and Misconceptions - Chris Brejon
• kofa’s inplementation of AgX in darktable
  • Blender AgX in darktable (proof of concept)
  • darktable/src/iop/agx.c at master · darktable-org/darktable · GitHub