Ability to get ElementRef of parent of ElementRef

[Boscop]

Please add the ability to get an ElementRef of an ElementRef's parent (and any ancestor/sibling), so that one can call .html() (and other ElementRef methods) on the parent :)

[causal-agent]

I think something like elem.parent().and_then(ElementRef::wrap).unwrap() would work.

[nathaniel-daniel]

Maybe it would make sense to add a shortcut method to ElementRef for such a common usecase?

[teymour-aldridge]

@nathaniel-daniel patches are welcome!