now that we can deal with module exotic property references nicely, we don't need to import all the node types in this file.  also fix some missing ;'s
remove the remaining named imports from ast-builder.  just use the exotic module object.
remove the rest of the large imports of node types from ast-builder, and just rely on the compiler optimizing away the member expressions.  also remove some vestiges of the old closure conversion since we've converted to the new way.