Add Lightbox to photos.html

I went ahead and added [Lightbox 2](http://lokeshdhakar.com/projects/lightbox2/) to photos.html. The only problem is that adding the `<a data-lightbox ...>` can't be done inline inside the `div.Collage`. It has to be done dynamically with a `.wrap()` call - which is _ok_, just not the most logical :P Take a look and tell me your thoughts...