Test for 'bind' and 'fnBind' breaks registering of Modernizr

Im building Modernizr via its API, and on resulted file have some code:

```js
// Defer to native .bind if available
  if ('bind' in Function.prototype) {
    return function fnBind (fn, that) {
      return fn.bind(that);
    };
  }
```

And this code is returned before Modernizr registers in a global scope:

```js
// Leak Modernizr namespace
  window.Modernizr = Modernizr;
```

Then, on my browserify shim I have ```undefined``` exports..