Fix PanZoom destroy. Test passes. Fixes #591.

git-svn-id: http://svn.openlayers.org/trunk/openlayers@2932 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Control/PanZoom.js

@@ -32,6 +32,20 @@ OpenLayers.Control.PanZoom.prototype =
                                              OpenLayers.Control.PanZoom.Y);
     },
 
+    /**
+     * 
+     */
+    destroy: function() {
+        OpenLayers.Control.prototype.destroy.apply(this, arguments);
+        while(this.buttons.length) {
+            var btn = this.buttons.shift();
+            btn.map = null;
+            OpenLayers.Event.stopObservingElement(btn);
+        }
+        this.buttons = null;
+        this.position = null;
+    },
+
     /**
     * @param {OpenLayers.Pixel} px
     * 
@@ -142,16 +156,6 @@ OpenLayers.Control.PanZoom.prototype =
         OpenLayers.Event.stop(evt);
     },
 
-    /**
-     * 
-     */
-    destroy: function() {
-        OpenLayers.Control.prototype.destroy.apply(this, arguments);
-        for(i=0; i<this.buttons.length; i++) {
-            this.buttons[i].map = null;
-        }
-    },
-    
     /** @final @type String */
     CLASS_NAME: "OpenLayers.Control.PanZoom"
 });