[Html-widget] formfu CSS online editor / viewer application

[Carl Franks]

I've created a CSS demo-app for formfu (Thanks to Zbigniew for the idea).
You can play with it here:
http://www.fireartist.com/html-formfu-cssapp/

It lets you add/edit different css pages, and then view a selection of
forms using that css.

At the moment, none of the displayed forms show any errors, but I'll
add a form which does once I've added L10N support, and the different
constraints have meaningful error messages.
I suppose if you really want to see an error, you could try editing a
css page with invalid input lengths ;)

To protect against the worst hacks, I've limited it to allowing 50 css
pages, each at 10KB. The css page name is limited to 20 characters.
And you can't edit/delete the 2 default css pages.

Cheers,
Carl