Lightbox: Add ability to filter Ajax response to selector

I need the ability to filter the Ajax response HTML to a particular 
selector before displaying it in the modal.

In the documentation for Magnific Popup [Ajax Type](http://dimsemenov.com/plugins/magnific-popup/documentation.html#ajax_type), it states you should do this 
via the parseAjax method.

I chose to include the data-* on the anchor, since the target selector can
vary based on the resource.

Hopefully something to this effect can be worked into the code.

Thanks guys