Remove dependency to json_object.
Add defaultClass to model object to allow it pretend as a fleet.
Update index.html to adopt the latest Polymer style.
Do not kill handle_error messages. These may contain exception messages which
is vital for debugging, even when in release mode.
Add sort links to the ship list.
Do not make fleet ships sortable; that is almost nonsense!
Implement actual sorting for name and level.
Implement other sort types.