animate scroll of mapview (by pixels, not lat long)
<p>I need to scroll a MapView programatically to make sure something is in view.  I know how many pixels it needs to scroll in each direction.  I see methods (in MapController) to animate it to a particular GeoPoint, and to scroll it by pixels without animation.  But nothing to do it by pixels, with an animation.  </p>

<p>What is an easy way to do this?</p>
