title: Google Maps Javascript Api V3 data.remove isn't removing a feature
body: <p>I'm working on a little pet project to edit personal maps by drawing polygons and am finding that when I call map.data.remove(feature), the feature is removed from map.data but isn't removed from the visual map.  Some of the javascript that doesn't relate to the data layer has been omitted.  What additional steps, removal, or function calls do I need to actually remove the feature from the map as well?</p>
  
  <pre><code>...
  function CustomMapType() {
  }
  CustomMapType.prototype.tileSize = new google.maps.Size(256,256);
  CustomMapType.prototype.maxZoom = 7;
  CustomMapType.prototype.getTile = function(coord, zoom, ownerDocument) {
      var div = ownerDocument.createElement('DIV');
      var baseURL = 'static/tiles/images/';
      var x = ((coord.x % Math.pow(2, zoom))
          + Math.pow(2, zoom)) % Math.pow(2, zoom);
      baseURL += zoom + '_' + x + '_' + coord.y + '.png';
      div.style.width = this.tileSize.width + 'px';
      div.style.height = this.tileSize.height + 'px';
      div.style.backgroundColor = '#1B2D33';
      div.style.backgroundImage = 'url(' + baseURL + ')';
      return div;
  };
  
  CustomMapType.prototype.name = "Custom";
  CustomMapType.prototype.alt = "Tile Coordinate Map Type";
  
  var map;
  var CustomMapType = new CustomMapType();
  
  
  //////////     Initializer Functions     //////////
  
  function initialize() {
    var styledMapOptions = { name: "Custom Style" };
    var mapOptions = getMapOptions();
    var data = getDataObject();
  
    data.addListener("click", function(event) {
      fillFormFromFeature(event.feature);
    });
  
    data.setStyle(function(feature) {
      var style = featureStyles[feature.getProperty('style')];
      return style
    });
  
  
    map = new google.maps.Map(document.getElementById("map_canvas"), mapOptions);
    data.setMap(map);
  
    map.mapTypes.set('custom',CustomMapType);
    map.setMapTypeId('custom');
    map.mapTypes.set(MY_MAPTYPE_ID);
  }
  
  function getMapOptions() {
    return {
      minZoom: 0,
      maxZoom: 7,
      isPng: true,
      mapTypeControl: false,
      mapMaker: true,
      streetViewControl: false,
      center: new google.maps.LatLng(65.07,-56.08),
      zoom: 3,
      mapTypeControlOptions: {
        mapTypeIds: ['custom', google.maps.MapTypeId.ROADMAP],
        style: google.maps.MapTypeControlStyle.DROPDOWN_MENU
      },
    };
  }
  
  function getDataObject() {
    return new google.maps.Data({
      controlPosition: google.maps.ControlPosition.TOP_CENTER,
      controls: ["Point", "Polygon"],
      featureFactory: function(featureGeometry) {
        var date = new Date();
        // TODO add code here for forming polygons.
        var feature = new google.maps.Data.Feature({
          geometry: featureGeometry,
          id: date.getTime(),
          properties: {
            'name': 'none',
            'style': 'new',
            'feature_type': 'new',
            'zIndex': '5000',
          }
        });
  
        document.forms["feature_form"]["feature_id"].value = feature.getId();
  
        map.data.add(feature);
        map.data.revertStyle();
        return feature;
      }
    });
  }
  
  
  ...
  </code></pre>