Event Bubbling demo, round 1
cleaner and more stable; also, stub out cancelling_box
Final example, plus some explanation inline
Scrap empty <head> section
Tidy
jquery 1.4.3 is sketchy about onload handlers; this demo shows that.
Bump to jQuery 1.10.0 to fix the onload bug demo'd in scratch/html5

Also, switch to using jQuery unminified, to make debugging weird things
like this in the future easier. We can switch to minified for deployment,
if and when we ever get there.