Get the height of content in previews, regardless of absolute/fixed
Get the height of content in previews, regardless of absolute/fixed

Resort to looping through the iframe DOM to get the element with the
lowest bottom position. This could be slow, but previews will have a
limited number of DOM nodes so it should be fine.

This should probably move to previews.js and use postMessage
asynchronously though.

paulwellnerbou/styledocco,ooooooo-q/styledocco,trungnghia112/styledocco,jacobrask/styledocco,paulwellnerbou/styledocco,trungnghia112/styledocco,ooooooo-q/styledocco