stereo_rfne: do subpixel rfnmt only in given window
photometry is no longer in ASP
Minor comment fixes
Document the --left-image-crop-win feature
stereo_rfne: Undo commit submitted by mistake
stereo_rfne: Undo commit submitted by mistake
point2dem: Rename DEMError to IntersectionErr

As it is not the DEM's error, it is actually the intersection error
between the 2 rays.