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
Should a new AJAX example file be added that shows the targeting of the element? The ajax1-en.html file doesn't have an element with <code>id="h5o-2"</code> so doesn't show anything different than the previous example.