Use Vedeu's new 'keys' API.
Vedeu no longer supports `cursor` like this.
Improve views;

In deprecating the subclassing of Vedeu::View and with the addition of Vedeu.render, rendering views has been simplified. Also, the controller has been refactored, and finally the Vedeu dependency version has been bumped to 0.2.1.
Configure application with sensible defaults.
Use #width instead of #viewport_width.
Bump vedeu dependency to 0.2.4.
Remove view tests; Vedeu has changed dramatically.