Overlays build-up

[davestewart]

Looks like past overlays build up when lightboxes are closed.

I added the following code to the close function and it clears the last-created overlay:

$(".js_lb_overlay").last().remove();

[Marza]

Would be better to re-use the overlay instead.

[pmb-sd]

I have noticed this behavior as well. they start to pile up after you close and reopen.