ImageBufAlgo::add a constant amount
oiiotool --cadd
Split parallel_image and DISPATCH macros into separate imagebufalgo_util.h
More IBA modernization: add, mul
More IBA modernization: colorconvert
IBA::computePixelStats refactor
Make it conform to modern IBA calling idiom -- including that it now will
gather stats about a specific ROI.
Merge pull request #556 from lgritz/lg-iba2

More IBA modernization: add, mul, colorconvert, computePixelStats