Formalize style-guide in a tool

[nexushoratio]

A toy python script was written to help with #173. We should finish is up and plug it in as a hook.

Either in Python, or make it an eslint plug in.

• [x] Submit what we have
• [x] Document
• [x] Fix to handle nested classes
• [x] #179 (or at least the nested GroupMode tests)
• [x] Finish migration
• [x] Plug into commit hook