I just added in an interesting feature: automatic namespace creation.
When using the `(import ...)` form, if the file tries to overwrite an already-existing variable, it will automatically create a new namespace. Otherwise, it won't.
This is mostly a performance optimization, since it's entirely possible to load every single file into a different namespace, but using this technique I avoid creating namespaces except when absolutely necessary, while still providing a reasonable amount of library isolation.
