Sourcecode of each example in a PRE element

Hi,

I basically just added small ```<pre class="sourcecode">...</pre>``` sections to the different examples that expand on hover. It's a bit easier to see the source code of examples that way instead of using a source code inspector or similar.

Sorry about the reformatting. My git/vim setup did that when I was not watching too carefully. Hope it's okay. Otherwise just ignore this pull request. :-)

Thanks for the Kitchensink work. It's really helpful.

Kind regards,

Steffen