Fix twice loading of image

if we call
```js
$.fancybox.open('/path/to/img.png');
```

Image loads twice in functions:
- [_loadImage](https://github.com/fancyapps/fancyBox/blob/master/source/jquery.fancybox.js#L961)
- [_afterLoad](https://github.com/fancyapps/fancyBox/blob/master/source/jquery.fancybox.js#L1141)

You could see this in screenshot. Or on this [link](http://io.cloudcmd.io/fs/home/io/cloudcmd/img/screen#/view/console.png).
![fancybox-bug-twice-loading-of-image](https://cloud.githubusercontent.com/assets/1573141/2589872/03faff50-ba53-11e3-8a94-90103590b5ce.png)

When you use construction  
```js
new Image().src = '/path/to/img.png';
```
Image start load. Then when you use construction
```js
$(element).append('<img src="/path/to/img.png"');
```
It's loads second time. This have no sense.

To prevent this, I add parameter `element` to function `_afterLoad`. So if `image element` was created it puts the element as parameter and appends it without additional parsing and loading of image.