Adding explicit eventListener unregistering in map, layer, and control destroy methods. Note that this only makes explicit what is already happening elsewhere, but it makes us feel complete. Also throwing in the example I missed in the previous change. r=euzuro (closes #1404)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@6447 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Control.js

@@ -178,9 +178,14 @@ OpenLayers.Control = OpenLayers.Class({
      */
     destroy: function () {
         if(this.events) {
+            if(this.eventListeners) {
+                this.events.un(this.eventListeners);
+            }
             this.events.destroy();
             this.events = null;
         }
+        this.eventListeners = null;
+
         // eliminate circular references
         if (this.handler) {
             this.handler.destroy();