title: Display a simple text label / descrption bubble when user taps on a OverlayItem in MapView
body: <p>I would like to further annotate the custom markers I have placed on a MapView (using ItemizedOverlay) by displaying a simple text label that appears for a particular item when the onTap event is fired. </p>
  
  <p>This is a trivial exercise in the Google Maps JavaScript API and in MapKit on iPhone, but it is not obvious to me what the best or easiest way to do this is on Android. </p>