Introducing "primaries" feature for sigmoid

[difrkaguilar (Franklin Aguilar Matos)]

Hello, I left a lights and smoke playraw to everyone who likes to test the primaries for Sigmoid.

Fashion Show, lights and smoke.

Hello fellows, Seeing the new modules added to darktable, primaries rgb and primaries for Sigmoid, I have revealed a picture of a recent event, a fashion show held in Havana, full of lights and smoke. I want to thank everyone involved in the development of darktable, and especially @flannelhead and @jandren for their contributions to make darktable an amazing raw developer. This is the version I made, but I would like to see and know other versions. [_DSF4783] The original RAW (RAF) _DSF4…

Thanks @flannelhead !!