Web Audio demos page

Hi all, I've recently spent some time making sure the demos page [1] that
I've maintained is now up-to-date with the latest spec (new API names,
etc.).  It's easily possible that I've missed something there, so please
let me know.  I'm interested in adding Mozilla to the intro section as
well, and will do so in the near future.

Cheers,
Chris

[1] http://chromium.googlecode.com/svn/trunk/samples/audio/index.html