To further help with tracking down the apperance of too much "Unknown User" in chatlogs, etc. temporarily change each instance of this in OpenSimulator so we can identify where it's coming from

For instance, the "Unknown User" in Util.ParseUniversalUserIdenitifer becaomes "Unknown UserUPUUI (class initials + method initials)
This is to help with http://opensimulator.org/mantis/view.php?id=6625