Lout and table running headers bug

[Jeff Kingston]

When I reviewed my email I found no recent reports of Lout crashing
on table running headers, but several of the headers being formatted
incorrectly (columns printed too far to the left).  I've done two
things for the next release:

* Found and fixed the formatting problem.  All the examples of faulty
  formatting sent to me now work correctly.

* Identified a second potential problem, which is that certain kinds of
  objects won't work inside table running headers under the current
  implementation.  I've documented this problem in the guides, and
  altered Lout to produce a reasonably clear error message and quit
  when this problem comes up.

* Identified a third problem, an inadequacy of the implementation
  which causes multiple appearances of the same running header on the
  same page to get their x positions mixed up.  I've hacked a solution
  to this that allows up to three copies of the same running header to
  appear on each page; a fourth on that same page will go wrong.  I've
  documented this in the guides.

Please do use table running headers once you get the next release,
and please do let me know of any remaining problems with them.  I
realize that it's been rather dispiriting to have this problem go on
so long without being addressed, but table running headers are probably
working now and if there are any remaining problems I now have time to
get onto them immediately they are reported.

Jeff Kingston