Message: Add option to print full event ID

Add the E format specifier to print the full EventIDBase of the event where the Message was emitted. E.g. the following

   MessageSvc.Format = "% F%40W%S%4W%s%e%7W%R%T %0W%M %E"

will result in [run,event,...] being appended to each message.

Also cleaned up some of the formatting code and its documentation.