Grand reorg for starters!

- Organize client side stuff under 'codepen/'
- Google App Engine gutter under 'appengine/'
- Add third party libraries and links in 'appengine/lib'
uglify css/html

Prepros temporary uncompressed files were submitted by mistake...
Add misc goodies

- Add 'Enter URL to read' input;
- Get rid of codepen.io hard-coded address;
- Relocate static files to '/assets' on server.