Adding the Avination calling card interface

OpenSim/Framework/ICallingCardModule.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using OpenMetaverse;
+using OpenSim.Framework;
+
+namespace OpenSim.Framework
+{
+    public interface ICallingCardModule
+    {
+        UUID CreateCallingCard(UUID userID, UUID creatorID, UUID folderID);
+    }
+}