Implemented login through Google accounts.

I used https://github.com/facebook/tornado/blob/branch2.0/demos/chat/chatdemo.py.
Added toolbar button at the top to show the username and a logout button.

The logout button has no conditionals on it, since any page that is loaded will automatically redirect to login, so currently the user cannot be on a page and not logged in.
Fixed logout button color.

Changed to green, since the purple was too dark to see. I don't like the green so much either, so I'll need to do more with it.
Changed the main site to just show the user's first name.

I also moved the json format as a multiline comment in the BaseHandler class.
Merge pull request #2 from ChodeGames/authentication

Add Authentication