Moving require statement closer to dependency

Instead of always requiring Nokogiri, I'm opting to require it as late
as possible.
Adding .hound.yml

Release the hounds of style!
Preparing for Rubocop autocorrector
Auto-correcting styles as per rubocop autocorrect

Script ran:
`$ rubocop -a -c ./.hound.yml`
Narrowing the scope of Hound
Appeasing the hound