Clean up app code

[lphillips]

A lot of the warnings in app.py are addressed:

• long lines
• unused variables and return values
• unused imports
• extraneous whitespace
• missing whitespace
• camelCase function names

A couple of errors where variables in the game module were accessed without the "game." scope were also addressed.

This PR doesn't address the game.py module since it doesn't have as many warnings and changes to address these warnings would affect game logic in places which we don't have good ways to test currently, so it doesn't seem worth it at the moment.