Get rid of ol.FeatureOverlay

This also introduces a wrapX option to the Draw, Modify and Select
interaction.

examples/icon-sprite-webgl.js

@@ -1,5 +1,4 @@
 goog.require('ol.Feature');
-goog.require('ol.FeatureOverlay');
 goog.require('ol.Map');
 goog.require('ol.View');
 goog.require('ol.geom.Point');
@@ -102,12 +101,14 @@ for (i = 0; i < featureCount; i += 30) {
   overlayFeatures.push(clone);
 }
 
-var featureOverlay = new ol.FeatureOverlay({
+var featureOverlay = new ol.layer.Vector({
   map: map,
+  source: new ol.source.Vector({
+    features: overlayFeatures
+  }),
   style: new ol.style.Style({
     image: icons[iconCount - 1]
-  }),
-  features: overlayFeatures
+  })
 });
 
 map.on('click', function(evt) {