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
The example text should also identify why it is different than the previous AJAX example (targeting a specific element).