The lighting is super crappy, and pretty much hacked in. Will
need to redo this properly soon. However, this verifies that
certain other parts of the code are (mostly) working properly.
The AssemblyBuilder is responsible for collecting the data needed
to actually create an Assembly. AssemblyBuilders are now the
only way to create an Assembly, which guarantees that Assemblies
aren't half-baked.
Also got instancing working with transforms and such. It may not
be _really_ working because I don't have a complex test case for
it yet. But that will come later.
