Add a method to flush the prim update buffers once a frame, since the timer

appear to be too slow to be useful, or fail too fire. I may remove the timers
as a consequence if this.

OpenSim/Region/Framework/Scenes/ScenePresence.cs

@@ -840,6 +840,8 @@ namespace OpenSim.Region.Framework.Scenes
                 }
             }
 
+            ControllingClient.FlushPrimUpdates();
+
             m_scene.StatsReporter.AddAgentTime(Environment.TickCount - m_perfMonMS);
         }