Update to use YUI3 and simplified HTML structure

Hi Jean-Michel,

I've rewritten the javascript and updated it for YUI3. As a result, I've been able to radically simplify the renderers - so they no longer use multiple renderer classes for example.

You may need to do some additional work to the stylesheets - it could probably do with a fixed width, and some trimming of old CSS selectors.

Hope this helps,

Andrew