Let .hasEvent work with array iteration methods.

This simple change lets `.hasEvent(event, element?)` work methods like `array.every` or `array.filter`. It checks if `element` is a number and if so it uses `this` as the `element`.

```js
['drag', 'dragend'].every(Modernizr.hasEvent) // defaults to 'div' in strict mode and `window` in non-strict mode
['drag', 'dragend'].every(Modernizr.hasEvent, 'img') // creates element on each iteration
['drag', 'dragend'].every(Modernizr.hasEvent, document.createElement('img')) // reuses same element
```
Explicitly supplying the <var>thisArg</var> avoids the strict mode difference.