Back out CMYK-to-RGB conversions. There is really no way to properly do CMYK-to...

Back out CMYK-to-RGB conversions.  There is really no way to properly do CMYK-to-RGB conversion without color management, which is out of scope for libjpeg-turbo.  Applications wishing to do a trivial conversion, such as was implemented in these routines, can simply request CMYK output and do the trivial conversion themselves (or, even better, use an OSS color management library.)  We should not encourage the use of in-library CMYK-to-RGB conversion as a substitute for color management.

git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@695 632fc199-4ca6-4c93-a231-07263d6284db