start tile & layer id's with standard strings, to avoid funky characters when later these ids are used as parameters

git-svn-id: http://svn.openlayers.org/trunk/openlayers@983 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer.js

@@ -62,7 +62,7 @@ OpenLayers.Layer.prototype = {
             this.name = name;
             
             //generate unique id based on name
-            this.id = OpenLayers.Util.createUniqueID(name);
+            this.id = OpenLayers.Util.createUniqueID("Layer_");
             
             if (this.div == null) {
                 this.div = OpenLayers.Util.createDiv();