* app/assets/stylesheets/ws1.css: Explicit large sizes for h1 and h2
* app/assets/stylesheets/code-playground.css.scss: Grow size of html preview frame
* app/assets/stylesheets/ws1.css: import webfont 'Ubuntu' for playground output
* app/assets/stylesheets/ws1.css: standardize text at 30 px, and add some sample color classes
* public/ws1.html: Some sample HTML for students.
moved stylesheet out of assets/ to stop confilcts