This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
Document the fact that the tracefile argument must lead to a regular file.
Also took the opportunity to remove the spurious "Errors" entry
relating to filenames with the high-order bit set and add $Id$.
(More of the same to follow if there are no objections).
