Detect whether 

This is not ready for merging! I'm just trying to get a early review since it's my first non-trivial contribution, and I want to make sure I'm doing it right :)

This has two main parts:

- It adds a test case that fails. Unfortunately, it fails with recursion error, so the failure is... ugly :)
- It adds the ability for scopes to detect if imports in it are absolute

This does not yet fix #239, but it will :)

Any and all comments welcome :)