update method of calculating neighbour distance based on boudning box distances (instead of ink to ink distances).  Also fix a couple of mis-references to the page variable.
update method of calculating neighbour distance based on boudning box
distances (instead of ink to ink distances).  Also fix a couple of
mis-references to the page variable.

scttl/marks_based_ocr,scttl/marks_based_ocr,scttl/marks_based_ocr