RFE: Including common camera XYZ matrices

[mattebb]

Thanks for this great tool, its fast, controllable and gives great results for a vfx pipeline.

I notice that some open source raw libraries like dcraw have a collection of common camera's XYZ matrices included in order to do automatic colour space conversions where supported. It doesn't seem like rawspeed in the source distribution for hdrmerge has this included though.

It would be really handy if hdrmerge had similar capabilities since it's a bit of a pain to go via DNG, extract the matrix, invert it, etc. Currently I'm just applying the inverted matrix as a post-process in Nuke, and then OCIO to convert from XYZ to ACEScg.

thanks