Plumb in the presence notifications and region shutdown/restart messages

from the presence module to the message server, through the user server
and on into the database. This should fix the "Already logged in" issue
that grids see after a sim crashes, or a user crashes out of a sim.
Not yet a 100% solution for friends, but getting there.

OpenSim/Data/MySQL/MySQLUserData.cs

@@ -891,5 +891,31 @@ namespace OpenSim.Data.MySQL
                 dbm.Release();
             }
         }
+
+        public override void LogoutUsers(UUID regionID)
+        {
+            Dictionary<string, string> param = new Dictionary<string, string>();
+            param["?regionID"] = regionID.ToString();
+
+            MySQLSuperManager dbm = GetLockedConnection("LogoutUsers");
+
+            try
+            {
+               dbm.Manager.ExecuteParameterizedSql(
+                        "update " + m_agentsTableName + " SET agentOnline = 0 " +
+                        "where currentRegion = ?regionID",
+                        param);
+            }
+            catch (Exception e)
+            {
+                dbm.Manager.Reconnect();
+                m_log.Error(e.ToString());
+                return;
+            }
+            finally
+            {
+                dbm.Release();
+            }
+        }
     }
 }