Testing out ChromaticAffineTransform.  Could still be some bugs.
(#467b)
debugged centered ChromaticAffineTransform (shifts not yet debugged)
(#467b)
better (faster) values for test_chromatic
(#467b)
debugged ChromaticAffineTransform shifts
(#467b)
Switch from 2x2 affine transform matrix (+dx, dy) to slightly cleaner 3x3 augmented matrix which incorporates dx, dy
(#467b)
Merge branch '#467b' into #467
Merge ChromaticAffineTransform experiments into #467