destroy icon on destroy

git-svn-id: http://svn.openlayers.org/trunk/openlayers@520 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Marker.js

@@ -33,11 +33,10 @@ OpenLayers.Marker.prototype = {
     destroy: function() {
         this.map = null;
         
-        // code to remove HTMLImage will go here
-        //  I realize now that it was not a good 
-        //  idea to give OpenLayers.Icon the 
-        //  'imageDiv' property.. that should be 
-        //  here. This is on my hot-list to fix
+        if (this.icon != null) {
+            this.icon.destroy();
+            this.icon = null;
+        }
     },
     
     /**