removing $window.off(.boxer) (clean up)

This clean up **$.window.off(".boxer")** is causing a problem with "close.boxer" event.

I'm attaching the "open" and "close" events on window object, like this:

```javascript
$(window)
    .on("open.boxer", function ()
    {
        // something
    })
    .on("close.boxer", function ()
    {
        // something else
    });
```

And when the boxer modal is closing (_onClose method), this code are cleaning my events on $(window) object.

I'm using JQuery 1.7.1 because my project uses a template with too much dependencies and obsolete jquery methods.