Add Grunt / JSHint support

You can now cd to the top-level directory and call "grunt" allowing you to lint your JS files.
Later I want to add support for minifying and uglifying our scripts and custom code using Grunt.
For now we can stick with this, because I'm not exactly sure how to make grunt play nice with Node.
TODO: figure out how to make node / express serve our files post-minification

QA: Confirm grunt is working on your machine