Cleanups

[Erotemic]

Hi, I'm learning how to use the script. In order to better follow the code I made some changes that make it easier to reason about:

1. I change the import * to explicit imports, so it's clear exactly what is needed from the scanner file
2. I moved the body of the if __name__ == '__main__': block into a function, which prevents the global namespace from getting cluttered
3. I removed an unused import.
4. Pep8 linting

There is a possibility that this is going to break the global ids variable, so I need to test it first, but I wanted to put this PR up to give a heads up that I'm working on cleaning the script up, and see if it's something you are interested in.

Other refactors that I'd like to perform are:

• Adding a config file so the user doesn't need to edit code
• Adding a CLI to point at relevant config files
• Example config files for different common migration use cases
• Linux testing and support