Full-screen mode.

This tutorial shows how to toggle between plugin and full-screen display.

It's built on top of helloworld.html; diff the two to see what changes were necessary.

Shortly after transitioning to full-screen mode, the teapot will automatically revert back to plugin mode, to demonstrate how programs can cancel full-screen mode on demand.

Show full-screen banner when not full-screen.
Revert back to plugin mode automatically after a few seconds of full-screen mode.