Thank you kindly, Nlin for a patch that:

Adds a new method to IClientAPI to allow adding message handlers 
for GenericMessages (of which "autopilot" is one). Part 2 adds a 
specific autopilot handler in ScenePresence.cs.
2) Removing unused variables and functions.
3) Simplifying the navigation logic in ScenePresence.cs. The 
original patch was somewhat complex because it included orientation
logic for a future enhancement of orienting the avatar to point 
towards the direction being walked. Currently this isn't working, 
though, so I removed the orientation code, which leaves just the 
smaller and hopefully simpler-to-understand movement code.

OpenSim/Region/Examples/SimpleModule/MyNpcCharacter.cs

@@ -991,5 +991,15 @@ namespace OpenSim.Region.Examples.SimpleModule
         public void SendTerminateFriend(UUID exFriendID)
         {
         }
+
+        #region IClientAPI Members
+
+
+        public bool AddGenericPacketHandler(string MethodName, GenericMessage handler)
+        {
+            throw new NotImplementedException();
+        }
+
+        #endregion
     }
 }