commit
For testing the new iteration, the texture cache disk download was written
into the main thread instead of into the separate threads. Now they're back
in separate threads again.
Also I think some of these files probably should have been in the previous
commit.
The new rendering pipeline strives to simplify the nodes themselves as much
as possible and move much of the logic to an external rendering engine. This
change removes all of the responsibilities that no longer belong to the
nodes themselves and will soon be folded into the renderer.