fix logic issue in url mapping, improve 404 handling, add property change component notifications

Oqtane.Shared/Shared/SiteState.cs

@@ -9,5 +9,10 @@ namespace Oqtane.Shared
         public string AntiForgeryToken { get; set; } // passed from server for use in service calls on client
         public string AuthorizationToken { get; set; } // passed from server for use in service calls on client
         public string RemoteIPAddress { get; set; } // passed from server as cannot be reliable retrieved on client
+
+
+        private dynamic _properties;
+        public dynamic Properties => _properties ?? (_properties = new PropertyDictionary());
+
     }
 }