Blender Git Loki

Restored code from over a year ago, tests to allow anti-aliased
shadowbuffers. At the time the results were not satisfying enough,
but we now suffer a shadow problem that might well be solved with
this feature.

Problem:
Temporal aliasing of shadowbuffers when small details move (like strands).

In this case it doesn't work to simply increase the shadowbuffer size,
because strands are pixel-sized. Huge shadowbuffers make strand shadows
almost disappear. So... the shadowbuffer resolution has to be not too high.

Instead of increasing the buffer size, we then create multiple buffers,
each on different subpixel positions (a bit like "FSA" :).

So! Shadowbuffer sampling then works as follows;

1) You take multiple samples in the shadowbuffer, on different locations
inside (or around) the rendered pixel.
That option was aready available as "Samp" button in Lamps

2) Set amount of sample buffers. It is default 1, but can be 4 or 9.

The results of setting it to '4' or '9' buffers you can see here:
http://www.blender.org/bf/filters/index3.html

Actually, deep shadowbuffers could solve it probably too! Anyhoo...