remove unused diff and diffABS functions from OpenLayers.Pixel

git-svn-id: http://svn.openlayers.org/trunk/openlayers@129 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Marker.js

@@ -38,7 +38,7 @@ OpenLayers.Marker.prototype = {
     generateMarker: function(pixel) {
         // Create a div here, and set the location to the pixel above modified
         // by the icon size.
-        var iconPosition = pixel.diff(this.icon.offset);
+        var iconPosition = pixel.add(this.icon.offset.x, this.icon.offset.y);
         var markerObject = OpenLayers.Util.createImage(this.icon.url,
                                                        this.icon.size,
                                                        iconPosition);