Fetch code using js and refresh_token using api-client gem

fetch_access_token logic as per the documentation at:
https://developers.google.com/glass/develop/mirror/authorization

https://developers.google.com/youtube/2.0/developers_guide_protocol_oauth2
https://developers.google.com/accounts/docs/OAuth2WebServer#handlingtheresponse
Complete signup using one-time flow logic
Remove unused gem and its settings
Downgrade to older google-api-client