Makes region crossings asynchronous. Moved the bulk of the original code out of ScenePresence and into SceneCommunicationService, where it should be (next to RequestTeleportToLocation). No changes in the crossing mechanism itself, yet. But this change opens the way to doing crossings as slowly as it needs to be, outside the simulator Update loop.

Note: weirdnesses may occur!

OpenSim/Region/Framework/Scenes/Scene.cs

@@ -3179,6 +3179,11 @@ namespace OpenSim.Region.Framework.Scenes
             return m_sceneGridService.CrossToNeighbouringRegion(regionHandle, agentID, position, isFlying);
         }
 
+        public void CrossAgentToNewRegion(ScenePresence agent, bool isFlying)
+        {
+            m_sceneGridService.CrossAgentToNewRegion(this, agent, isFlying);
+        }
+
         public void SendOutChildAgentUpdates(AgentPosition cadu, ScenePresence presence)
         {
             m_sceneGridService.SendChildAgentDataUpdate(cadu, presence);