Add measure of number of inbound AgentUpdates that were seen as significant to "show client stats" (i.e. sent on for further processing instead of being discarded)

Added here since it was the most convenient place
Number is in the last column, "Sig. AgentUpdates" along with percentage of all AgentUpdates
Percentage largely falls over time, most cpu for processing AgentUpdates may be in UDP processing as turning this off even earlier (with "debug lludp toggle agentupdate" results in a big cpu fall
Also tidies up display.

OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs

@@ -5565,6 +5565,8 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
         #region Packet Handlers
 
+        public int TotalSignificantAgentUpdates { get; private set; }
+
         #region Scene/Avatar
 
         private bool HandleAgentUpdate(IClientAPI sener, Packet packet)
@@ -5614,6 +5616,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                 if (update)
                 {
 //                    m_log.DebugFormat("[LLCLIENTVIEW]: Triggered AgentUpdate for {0}", sener.Name);
+                    TotalSignificantAgentUpdates++;
 
                     m_lastAgentUpdateArgs.AgentID = x.AgentID;
                     m_lastAgentUpdateArgs.BodyRotation = x.BodyRotation;