Style clean-up and small refactors

Hi there,

This is mostly a cosmetic PR and small refactoring to clean up styles according to the [Ruby Style Guide](https://github.com/bbatsov/ruby-style-guide). I find this much easier to read that what Hound suggests (single quoted strings, for example). Feedback welcome.
IMO hard enforcement on 80 characters to a line makes code easier to read. It can also be a possible code smell that something needs to be refactored/extracted to a method if the line is over 80 chars.