Caching array length instead of accessing it with each iteration. r=crschmidt (closes #1636)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@7627 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer/FixedZoomLevels.js

@@ -78,7 +78,7 @@ OpenLayers.Layer.FixedZoomLevels = OpenLayers.Class({
 
         var props = new Array('minZoomLevel', 'maxZoomLevel', 'numZoomLevels');
           
-        for(var i=0; i < props.length; i++) {
+        for(var i=0, len=props.length; i<len; i++) {
             var property = props[i];
             this[property] = (this.options[property] != null)  
                                      ? this.options[property]