Skeleton for JavaScript components using Backbone view.
Implement model serializer as JSON renderer adapter.

Instead of registers JSON adapter to `fanboi2.models.Base`, the adapter
now registers to the model class itself. This gives us more flexibility
such as able to add extra field such as `body_formatted` that calls
formatter, etc.
Annotate methods type as a hint to IDE (PyCharm, IntelliJ, etc.)

This annotation will help IDEs to better inspect the code as it is now
aware of param types and return types. See also the below URL:
https://www.jetbrains.com/pycharm/webhelp/type-hinting-in-pycharm.html
Bring back the orange bar in mobile view.

Turns out it's really hard to add header menu with the combined header
layout, so let's bring the orange bar back for now...