Handle rails 4.1 not symbolizing nested hashes

So it appears rails 4.1 changed the way their convert the cookies to not try and symbolize nested keys 

http://guides.rubyonrails.org/upgrading_ruby_on_rails.html#cookies-serializer

This simply tries both keys. A nicer way would be use hashwithindifferentaccess but wasn't sure if that was safe to use here? If you would like the gem to depend on ActiveSupport as well I am happy to switch it out.