Color picking in CMYK
A few changes:
- Right now, color picking in CMYK predates support in bablGEGL, therefore it obviously doesn't use babl conversion. We should change it to use babl.
- If no CMYK profile was set as soft-proof profile, I wonder if we should even propose the CMYK option. Probably it should be grayed out. CMYK without a profile is even more meaningless as there is no single default space AFAIK (unless RGB which has sRGB).