SCSS Refactor

This is a great directive! Awesome! I wanted to clean things up a little bit and make it even better. I apologize for throwing the mass of commits your way but I figured it would be great to keep your repo the primary and I'm now running low on battery :wink: 

Most notably, I've refactored the SCSS to use relative sizes so the entire chart can be scaled by changing the font-size property on the `#punch-card` element. (screenshot below) 

![chart-scale](https://cloud.githubusercontent.com/assets/1479206/3511679/d97e37fa-06b1-11e4-86de-a6208bab8ad2.gif)

Other changes include: 
- Replaced JS logic to assign even/odd classes with css pseudo selector (`:nth-child(even/odd)`)
- Updated dev dependencies, added watch task for compilation of assets
- Cleaned up Repo

Great work @grsmv! :+1: :+1: