More things to catch
Proof of concept search for undefined and unused variables
Walk children scopes
Distinguish unused name types
Comment out debug prints
Make iron work with external file
Primitive support for builtins
Make class def a write
Fix a bug with implicitly nonlocal names
Process all passed files
Handle vararg and kwarg
Better scope stringification
Scope non-locals better
Exclude methods and other class attrs from "never used" check