Replace Faraday with the HTTP gem
Revert "Redefining unary ! is not allowed in Ruby 1.8.7 :frown:"

This reverts commit 29207afd36771ab6f8583238bd7919aa4049f586.
Drop support for Ruby 1.8.7
Reconfigure RuboCop for Ruby 1.9.3 and greater
Convert hash rockets to colons
Always return a valid JSON response