WyC: Updated CodeGenerator to Compile.

The code generator now compiles with the new notion of
AttributableBlock.  However, it doesn't actually create any appropriate
AttributeMaps, which is a problem.  Furthermore, to make it compile, I
have stripped out a lot of stuff related to the expansion of types.
This has all been put into a new transform called TypeExpansion, which
currently is completely broken and I will need to fix up later.