Major changes in interregion communications. This breaks compatibility with older versions, and may result is all sorts of weirdnesses when interacting with sims in older versions. Changes:

- Introducing synchronous Teleports. Now the receiving region calls back the sending region after the client has been made a root agent there, that is, after client sends CompleteMovement to the destination.
- SendCloseAgent moved from OGS1 Remoting to RESTComms.

OpenSim/Framework/ChildAgentDataUpdate.cs

@@ -144,6 +144,7 @@ namespace OpenSim.Framework
 
         byte[] VisualParams;
 
+        public string CallbackURI;
 
         public OSDMap PackUpdateMessage()
         {
@@ -191,6 +192,9 @@ namespace OpenSim.Framework
 
             // Last few fields are still missing
 
+            if ((CallbackURI != null) && (!CallbackURI.Equals("")))
+                args["callback_uri"] = OSD.FromString(CallbackURI);
+
             return args;
         }
 
@@ -284,6 +288,9 @@ namespace OpenSim.Framework
 
             if (args["active_group_id"] != null)
                 ActiveGroupID = args["active_group_id"].AsUUID();
+
+            if (args["callback_uri"] != null)
+                CallbackURI = args["callback_uri"].AsString();
         }
 
         public AgentData()