Thoughts on making Cycles into a spectral renderer

[Eary]

@brecht

Because I don’t think the color is representative of what it’s doing. High values will show white, low values black, regardless of the color tint.

But, we should really add Red/Green/Blue labels to those buttons. We just haven’t gotten to it yet.

I wonder what the subsurface radius is actually doing in the spectral branch. Is it being treated as color and converted to spectra or what? Would the change of the scene_linear working space affect this process? Does it still make sense to be a Non-Color and yet RGB vector in spectral?