documentcloud/underscore — pull request #901 by hokaccha (2012-12-14 01:53:47+00:00)
Title: _.isNaN(new Number(NaN)) should return false

ECMAScript6's `Number.isNaN` returns false.

```javascript
Number.isNaN(new Number(NaN)); //=> false
```

see also:
http://wiki.ecmascript.org/doku.php?id=harmony:number.isnan

If `_isNaN` emulates `window.isNaN`, args should be converted to Number.

```javascript
_.isNaN = function(obj) {
var number = +obj;
return number !== number;
};
```