* binarization/internal/first_pass_functor.hh: Use
	sauvola_threshold routine.

	* binarization/sauvola_threshold.hh: Remove debug and fix invalid
	read in integral image.

	* canvas/integral_browsing.hh,
	* subsampling/integral_single_image.hh: Fix stats computation.

	* src/binarization/sauvola_ms.cc: Fix window parameter and make
	debug output optional.