Make controls smaller for online demo

The dat.gui controls were taking up a lot of scene real-estate, such
that you could not see the frustum view. Condensed. Also, jshint
cleanups.
JSHint cleanups of demos, fix energy balanced demo

Cleanup of demos of all JSHint problems. Fix container of energy
balanced demo so that it displays properly.
Add note about tessellation for drinking bird

SphereGeometry and CylinderGeometry need tessellation in order to pass
the question.
Better display of unit 9 exercises

Simply add links to the exercises menu
Merge pull request #34 from erich666/master

Make controls smaller for online demo