Add a proper web UI

This pull request moves success to a template, adds a user_data function, and adds a settings view.

Thanks to @Neal for suggesting colours and commenting on the UI.

![Success](https://cloud.githubusercontent.com/assets/5637/3519717/8f89b72a-071d-11e4-96c2-a6dab66598da.PNG)
![Settings](https://cloud.githubusercontent.com/assets/5637/3519716/8cbf2958-071d-11e4-99b9-936a84b066ee.PNG)

Let's use the new Hash format?
```ruby
erb :settings, locals: { user: user, cards: cards_data(access_token), pebble: params[:pebble], version: params[:version] }
```