Make it an AMD module about responsive-nav.js

[reintroducing]

+1 to this, looks like all the things I want out of this wonderful script have already been filed :) The readme states that it supports requirejs but it actually doesn't work unless you shim the library properly and export responsiveNav. Removing the shim breaks the require link and it throws an error. This should be implemented properly and can be done relatively easily (http://javascriptplayground.com/blog/2012/10/making-your-library-amd-compliant/).

[reintroducing]

I actually just tried this and all it takes is this:

window.responsiveNav = responsiveNav;

if (typeof window.define === "function" && window.define.amd) {
    window.define("responsiveNav", [], function() {
      return window.responsiveNav;
    });
}

I forked your repo and added the change but to be 100% honest I'm still trying to wrap my head around pull requests and git in general so this is my best way to communicate this to you :)

[timkelty]

+1