feat: update 'samples/overlay-hideshow' to account for tilt (v=beta)

I noticed that the [google.maps.OverlayView](https://developers.google.com/maps/documentation/javascript/reference#OverlayView) in 'overlay-hideshow' sample gets distorted when the map is tilted (beta feature).

See example (hold shift and drag with the mouse to tilt and rotate the map)
https://jsfiddle.net/jq5f0zsk/1/

The issue becomes apparent when the tilt > 0

Is there a way to configure the OverlayView to remain "flat"?
Alternatively, perhaps the 'div' can be transformed (3d rotation) to compensate for the tilt and rotation of the camera?

Thank you!