Add How-To section in about.html for use on other sites

[jakefeasel]

Include an example of embedding a fiddle within iframe and also loading via AJAX requests like so: http://jsfiddle.net/S3DR9/. Possibly a full explanation of the REST-ish "API" that is available for extensions, plus a suggestion that interested ruby/python/whatever developers build a nice database abstraction layer for use in web sandboxes.