cache: Fix thread-safety of debug commits

They were placed in such a manner to cause dead locks. Now they are
moved above lock acquistion.
image: Have block rasterize share handles between instants

This saves a good deal of memory as multiple instances will now be
able to share their bits of cache. This makes the cache more
efficient!
Cache: Remove unneeded scoped watch

It allocates a lot of memory.
all: Relicense for 2013