Fix allocation and stride bugs in ImageInput::read_tiles. When reading tiled images, where the image is not a whole number of tiles, this bug could misallocate and run off the end of the buffer while dealing with the partial tiles on the right or bottom edge of the image.
Fix allocation and stride bugs in ImageInput::read_tiles.
When reading tiled images, where the image is not a whole number of tiles,
this bug could misallocate and run off the end of the buffer while dealing
with the partial tiles on the right or bottom edge of the image.

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