Fix negative values in HOG calculation
Fix negative values in HOG calculation

Values were not being rounded correctly due to truncation
of the interger cell size in pixels. This corrects that
by using the original code used by @nontas in Matlab.

menpo/menpo,yuxiang-zhou/menpo,menpo/menpo,yuxiang-zhou/menpo,patricksnape/menpo,grigorisg9gr/menpo,yuxiang-zhou/menpo,menpo/menpo,patricksnape/menpo,grigorisg9gr/menpo,grigorisg9gr/menpo,patricksnape/menpo