Harder Better Faster Stronger... V3

Ok, so I decided to scrap v2 and do a complete and total rewrite (again).

* there is only ever one .superbox-show DOM element created,   
* it's inserted after the entire row you happened to be clicked on and stays in the right place even after a window resize   
* there is now keyboard navigation
* scrolling takes you to the top of the row of images (your original intent I believe)
* usage and all v2 options and features are intact

I think v3 is the one worth building on. Ignore the v2 pull request.