Add concatenation

This PR accomlishes 2 things:

* Simplifies the uglification process a little bit
* Adds on file concatenation for easier SASS compiling

I realized that the grunt sass task can't handle mutliple sass files and compile them into one .css file. I don't like that; I want to be able to add a .scss file in to the sass directory, and just know that grunt will magically add that into the main `screen.css` file.

So, in order to make that happen, I added the `grunt-contrib-concat` plugin, which will watch for any changes in the `sass` directory, and concatenate them into a single `concat.scss` file. THEN, the grunt-contrib-sass task fill fire, because it's watching for that particular `concat.scss` file to change, and all will be well.

Does this make sense? I can explain it in person as well.