Use `:delete_all` over `:destroy` dependency

Deletes receipts in one SQL query instead of one for each receipt.
Upgrade to devise 2.2
Use email matchers in feature specs

Otherwise, only include them in mailer spec
Update draper to 1.2.0
Update simple_form to 2.1
Update gem that don't require code changes
Update production gems
Update testing gems
Update factory_girl
Update bourbon
Update capybara and poltergeist
Use Node#synchronize over sleeping