rubocop, a little more compliant

Why Rubocop? "The main benefit is social, I guess. People not complaining/noting those minor style differences, because they're compliant."

  - 33 files inspected, 516 offenses detected, 394 offenses corrected
  - there is more to fix, but the unimportant ones are now passing

So, depending on how you feel about Rubocop, this can be useful/useless.

This PR was done exclusively by `rubocop -a` (auto-correct) and then running `bundle exec rake test`.
@igas hm this would make it harder to move rules between checksets, I'll probably remove this.