Make select interaction create its FeatureOverlay

You can now configure it with a `style` option.

src/objectliterals.jsdoc

@@ -440,7 +440,7 @@
  *     features should be selected.
  * @property {Array.<ol.layer.Layer>|undefined} layers Layers.  Zero or more
  *     layers from which features should be selected.
- * @property {ol.FeatureOverlay} featureOverlay Feature overlay.
+ * @property {ol.style.Style|Array.<ol.style.Style>|ol.feature.StyleFunction|undefined} style FeatureOverlay style.
  */
 
 /**

src/ol/interaction/selectinteraction.exports

@@ -1,3 +1,3 @@
 @exportSymbol ol.interaction.Select
-@exportProperty ol.interaction.Select.prototype.getFeatureOverlay
+@exportProperty ol.interaction.Select.prototype.getFeatures
 @exportProperty ol.interaction.Select.prototype.setMap

src/ol/interaction/selectinteraction.js

@@ -69,18 +69,20 @@ ol.interaction.Select = function(options) {
    * @private
    * @type {ol.FeatureOverlay}
    */
-  this.featureOverlay_ = options.featureOverlay;
+  this.featureOverlay_ = new ol.FeatureOverlay({
+    style: options.style
+  });
 
 };
 goog.inherits(ol.interaction.Select, ol.interaction.Interaction);
 
 
 /**
- * @return {ol.FeatureOverlay} Feature overlay.
+ * @return {ol.Collection} Features collection.
  * @todo stability experimental
  */
-ol.interaction.Select.prototype.getFeatureOverlay = function() {
-  return this.featureOverlay_;
+ol.interaction.Select.prototype.getFeatures = function() {
+  return this.featureOverlay_.getFeatures();
 };