Code refactoring

I was using Churn in a gem of mine and thought I needed a new feature. While developing that feature, I ended up refactoring a bit of Churn's code. In the end, I realized I didn't need that feature after all :expressionless:

However, not every effort has to go to waste. I hope some of these changes are useful.

I apologize for all the whitespace fixing, but my text editor does that for me :laughing: Every file I touched had its whitespace fixed, so I bundled all that into a single commit.