Improving Use of Scoping

[DavePearce]

Currently, the way that buildModuleScope() works is not ideal at all. Realistically, we need to remove the Environment entirely from the resolution process, and only generate the schema after resolution. The problem is that, at the moment, the ModuleScope is only constructed after assignments have been resolved. However, in the future when we have defcompute constructs then this will not work as we may need to resolve expressions at the same time?