Fixed the update of items in the priority queue to enable both

types of property updates to be specified. Not sure if one form
of property update should supercede another. But for now the old
OpenSim behavior is preserved by sending both.

OpenSim/Framework/IClientAPI.cs

@@ -575,6 +575,11 @@ namespace OpenSim.Framework
         public ISceneEntity Entity;
         public uint Flags;
 
+        public virtual void Update(IEntityUpdate update)
+        {
+            this.Flags |= update.Flags;
+        }
+
         public IEntityUpdate(ISceneEntity entity, uint flags)
         {
             Entity = entity;