bmp spec allows height to be negative. If so - scanlines are stored top-down. This change assure that we always pass positive height to ImageSpec and that we read scanlines top-down when height is less then zero and bottom-up when height is greater then 0
bmp spec allows height to be negative. If so - scanlines are stored top-down. This change assure that we always pass positive height to ImageSpec and that we read scanlines top-down when height is less then zero and bottom-up when height is greater then 0

git-svn-id: c3edda122e248ef33995da003806c930f62b9468@614 31904243-a364-42ac-a3db-9305396518ba

sambler/oiio,mcanthony/oiio,bdeluca/oiio,scott-wilson/oiio,scott-wilson/oiio,bdeluca/oiio,micler/oiio,bdeluca/oiio,mcanthony/oiio,OpenImageIO/oiio,micler/oiio,lgritz/oiio,mcanthony/oiio,YangYangTL/oiio,OpenImageIO/oiio,micler/oiio,jeremyselan/oiio,lgritz/oiio,sambler/oiio,lgritz/oiio,YangYangTL/oiio,scott-wilson/oiio,mcanthony/oiio,lgritz/oiio,cwilling/oiio,scott-wilson/oiio,sambler/oiio,cwilling/oiio,sambler/oiio,OpenImageIO/oiio,YangYangTL/oiio,YangYangTL/oiio,jeremyselan/oiio,cwilling/oiio,cwilling/oiio,OpenImageIO/oiio,jeremyselan/oiio,micler/oiio,bdeluca/oiio