small new fixes

[ibaranov-cp]

• cherrypy is now a requirement, should be added to requirments.txt
• Rename Product ID as Device Type ID to more closely match Amazon description (minor confusion)
  Seems to work now! :)

[ewenchou]

Thanks for the suggestions. I've updated it. Kept cherrypy in auth_web_requirements.txt since it isn't actually required by alexa_client itself.