Blender Git Loki

Tomato Cycles: resolve slowdown introduced by interactive samples view commit

Update samples displayign in the interface once in a whiel only
(currently once in 1 sec). This still keeps rendering interactive
enough for artists and it eliminates slowdown caused by constant
uploading sampels from GPU to host.

This also allowed to get rid of hack with storing render result
in render buffers, due to it's not so big overhead ow to create
render result when sample needs to be updated.

Tests made with different files shows that now render speed is
really close to oroginal speed from before we started hackign
into this stuff.

There still some issues with interactive update when rendering
several render layers, but that seems to be irrelivant to all
this sampels commtis, so woudl look into this as a separate
patch.