Convert images to 8-bit PNG.

Also move the unused images to a subfolder.
Add normalize.css and html5shiv.js.

This way older browsers should work better.
Remove unneeded indentation from code blocks.
Inline highlight.js in the html.

It's small enough and this way we save one http request.
Update example/mocha.css.

Add missing vendor prefixed properties and fix font-size for `#error`.
example/tests.html: use the favicon.