Removing no longer needed code.

Thanks @elemoine for catching the IE6 reflow in Tile/Image.js.

lib/OpenLayers/Layer/Grid.js

@@ -651,17 +651,6 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
             this.map.getZoomForResolution(resolution) + (this.zoomOffset || 0);
     },
 
-    /**
-     * Method: getResolutionScale
-     * Return the value by which the layer is currently scaled.
-     *
-     * Returns:
-     * {Number} The resolution scale.
-     */
-    getResolutionScale: function() {
-        return parseInt(this.div.style.width, 10) / 100;
-    },
-
     /**
      * Method: applyBackBuffer
      * Create, insert, scale and position a back buffer for the layer.