Blender Git Loki

FSA: tweaked merging samples with filter to correctly map edges of the
images. Found method that doesn't require image to be rendered larger.

Note: assembling pre-rendered parts that are result of FSA renders might
still give minor visible artefacts on edges; however, we should include
such render methods in the render pipeline, so multiple computers can
each render parts, save all samples, and have 1 computer assembling and
compositing all. This is for another project... :)