* Rewrote ClientManager to remove Lindenisms from OpenSim core, improve performance by removing locks, and replace LLUDPClientCollection

* Removed the confusing (and LL-specific) shutdowncircuit parameter from IClientAPI.Close()
* Updated the LLUDP code to only use ClientManager instead of trying to synchronize ClientManager and m_clients
* Remove clients asynchronously since it is a very slow operation (including a 2000ms sleep)

OpenSim/Region/ClientStack/LindenUDP/LLUDPClient.cs

@@ -181,7 +181,6 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         /// </summary>
         public void Shutdown()
         {
-            // TODO: Do we need to invalidate the circuit?
             IsConnected = false;
         }