which encapsulates a cmsHTRANSFORM and does all the pixel format
conversion magic. It has API to create transforms and proofing
transforms, and to convert pixels arrays and GeglBuffers.
Before, each place which has a transform had to keep around the
transform and its input and output Babl formats, and had to implement
lots of stuff itself. Now all that lives in GimpColorTransform,
removing lots of logic from many places, and pretty much removing lcms
from the public API entirely.
This removes including <lcms2.h>, LCMS_LIBS and LCMS_CFLAGS from
almost all directories and potentially allows to replace lcms by
something else.
