Modular-izing the javascript

So, to start, I love this tutorial. When I first saw it, I went through it three or four times just to get it in my head. I've been looking for something like this for a while.

However, being a developer, I wanted to check out the logic and code, and found it a bit tough to get my head around, given the organization. With this PR, I'm trying to lower the bar to see what you're doing to make the pieces work, and hopefully enable you to more quickly create additional pages! I figure, if I can make your life easier with software help, perhaps you can make mine better with more hardware lessons!

Let me know your thoughts - the basic gist to get things going locally is:

1. Install [Node and NPM](http://nodejs.org/)
1. Run `npm install -g gulp`
1. Run `npm install` in the project root
1. To build the javascript, run `gulp build`, or to set it watching run `gulp watch`

If all you want to do is work in HTML or styling, none of the above is necessary - this is only for managing a more modular javascript project. 

Let me know what you think!