added optional parameter (pointing correction matrix) to the
rectification.rectify_pair function
fix bug
added shear to the error model
Merge branch 'master' of github:gfacciol/s2p

Conflicts:
	python/homography_cropper.py
Merge branch 'master' of github.com:gfacciol/s2p
instead of a fixed intensity range use qauto to generate the visualization