Make setup instructions clearer
Pull HTML and styles via JSONP when required.

This approach delays loading the markup and styles until they are
actually required. ie: When the widget is actually loaded.

This way we minimise end user bandwidth.

It also decouples the HTML from the JS and makes it more
straightforward to drop the jQuery dep.
Make embed tag work on the homepage

Test this by loading http://localhost:5000 and entering
helpful_embed.toggle($('#embed_target')) in the js console
Merge pull request #22 from davidbanham/master

Pull embed markup+style via JSONP