Uncaught TypeError: Cannot read property 'error' of undefined

Using these code

``` html
<script type="text/javascript" src="https://cdn.jsdelivr.net/blazy/1.4.1/blazy.min.js"></script>
<script>
    ;(function() {
        // Initialize
        var bLazy = new Blazy();
    })();
</script>
```

will thrown this error: `Uncaught TypeError: Cannot read property 'error' of undefined`.
Even with no elements in use. Even with 1.4.0.
