adds app.styl

Accomplished:
- Direct 1:1 translation of app.css to a stylus file.

To Do:
- Finish setting up Grunt to auto compile .styl files
- Refactor code to be DRY.

Note - until I get hte gruntfile working 100%, you'll have to manually compile the stylus.
install stylus `npm install -g stylus` then
use `stylus public/css/app.styl` from the root folder.