title: Iterate features added by my code?
body: <p>How can I iterate features my users have added to a google.maps.map?</p>
  
  <p>I can do this with the data layer just fine -- features added by map.data.loadGeoJson(). </p>
  
  <p>But how do I find other features without duplicating the data in the map? </p>
  
  <p>Examples:
  * Markers the user has added with my DrawingManager? 
  * Overlays I have added with code? </p>
  
  <p>Using events and stuff to track everything seems redundant because the data is in the map. Most mapping libraries let programmers iterate the layers of a map and get the features in those layers. Is this missing from Google Maps? </p>