code to not compile when used with the mingw-cross-env project.

automatically size itself properly when a zoom is in effect and you place a new
image into it.

in you could see that some of the pixels which are inside the rectangle were
outside the overlay.  Specifically, the right column and bottom row was outside
the overlay rectangle.  This has been fixed.  Now all pixels which are supposed
to be part of a rectangle are drawn as being inside the overlay rectangle.

type of scalar used to store the sums.

compile in more contexts.

grid.  So now you can convert from image to hog instead of just hog to image.  Also added some
related unit tests.

--HG--
rename : tools/imglab/src/convert_pascal_voc.h => tools/imglab/src/convert_pascal_xml.h

--HG--
rename : tools/imglab/src/convert_pascal_voc.cpp => tools/imglab/src/convert_pascal_xml.cpp