init lightbox

dunno if you want this in here, but figured i would make a PR so you could comment/check it out
You'll probably want a structure like:

```html
  <!-- this is to cover the rest of the page -->
  <div class="lightbox-background .js-lightbox-dismiss"></div>

  <!-- this is the only content above the lighbox-background -->
  <div class="lightbox-container">
   <div class="lightbox-content js-lightbox-content">
   </div>
   <a href="#" class="lightbox-dismiss js-lightbox-dismiss">x</a>
  </div>
```
Then your `removeSelf` events would be bound to .js-lightbox-dismiss