Allow for using a different set of default behaviors.

The default behavior of dragging and wheel zooming feels specific to 2D maps. So I think it makes sense to introduce a special type of controls (ol.control.DefaultControl) that implement default behaviors. This change also re-introduces the Navigatin control, which is a container for the default behaviors that were previously defined in the map handlers. Maybe this control needs to be renamed to Navigatin2D in the future, and there could be a different Navigation control for 3D maps.

src/ol/Map.js

@@ -88,6 +88,12 @@ ol.Map = function() {
      * @type {Array}
      */
     this.controls_ = null;
+    
+    /**
+     * @private
+     * @type {ol.control.DefaultControl}
+     */
+    this.defaultControl_ = null;
 
     /**
      * @private
@@ -157,7 +163,7 @@ ol.Map.DEFAULT_TILE_SIZE = 256;
   @const
   @type {Array.<string>}
  */
-ol.Map.DEFAULT_CONTROLS = ["attribution", "zoom"];
+ol.Map.CONTROLS = ["navigation", "attribution", "zoom"];
 
 /**
  * @return {ol.Loc} Map center in map projection.
@@ -443,6 +449,20 @@ ol.Map.prototype.addLayers = function(layers) {
 };
 
 
+/**
+ * @returns {ol.control.DefaultControl}
+ */
+ol.Map.prototype.getDefaultControl = function() {
+    return this.defaultControl_;
+};
+
+/**
+ * @param {ol.control.DefaultControl} control
+ */
+ol.Map.prototype.setDefaultControl = function(control) {
+    this.defaultControl_ = control;
+};
+
 /**
  * @param {Array.<ol.control.Control>|undefined} opt_controls
  */
@@ -483,7 +503,7 @@ ol.Map.prototype.setContainer = function(container) {
     this.createRenderer();
     //TODO Controls could be set earlier, but we need to deal with content that
     // controls place on overlays.
-    this.setControls(ol.Map.DEFAULT_CONTROLS);
+    this.setControls(ol.Map.CONTROLS);
     // conditionally render
     this.conditionallyRender();
 };