Copy over data attrs from video el to wrapper el.

We should be mimicking the video element more closely, so, the wrapper el should not be losing any of the data-attributes that were added before the creation of a player.
I'll change to use `vjs.obj.each`.
As for createEl, that won't work currently because `vjs.createEl` will copy items over via bracket-notation unless it is an `aria-` or `role` attribute which won't pick up things like `class` attribute or `data-` attribute which can't be set via the bracket-notation.