Avoid gaps between box filter kernels.
Remove unused functions.
Starting to implement downsampling.
Basic downsampling algorithm works for uniform sampling.
Fix nonuniform downsampling.
Fix upsampling, avoid dereferencing in an inner loop.
Fix non uniform scaling where out_w > in_w && out_h < in_h.
Fix non uniform scaling where out_w < in_w && out_h > in_h.
Make consistent tests for whether we're doing upsampling or downsampling of width and height. Don't request memory for horizontal buffer or encode buffer if we don't need it.
Keeping a list of suggestions so I don't forget them.