Prevent race condition when queue file is attached
to consult message, by spooling file before list_access_check()
is called in Mj::Resend::post().  Remove "unspooled_file" variable.
Surprise!  More bounce handling work.
Clarify help page.
Allow multiple tokens to be handled at once using checkboxes
in combination with the result of the showtokens command.
Allow multiple addresses to be unsubscribed or unregistered
using checkboxes in combination with the result of the who
command.
Fix some warnings and remove a debugging statement.
Rewrite Majordomo::_show and Mj::Format::show in preparation for displaying
bounce data.
Display some bounce data in 'show' output.  More data is available, but the
output is pretty long as it is.
Fix sime who-enhanced breakage I introduced with who-export.
Make some bounce handling parameters configurable.
Make delivery engine probe bouncing addresses.
(post) Do not purge the acknowledgement, since that would unlink
the spool file.
Add who-bounces-enhanced to the command menu.
(_list_file_get):  Add "DEFAULT:" to the file search path.

(who_chunk, Mj::Format::who):  Add preliminary code for who-bounces:
Number of bounces in the past week is displayed.  Only addresses
with bounces are shown.

(_show):  Include undescribed class in output, for use by mj_wwwusr.
Adapt showdata() to the new data returned by the show core subroutines.
Recognize a few additional bounce formats (Post.Office, Lotus, and another
old Sendmail version).
Bounce parsing tweaks.
Fix logic error in expire_subscriber_data.
Put token in envelope sender and use it to automatically delete tokens
  that bounce.
Fix bad crasher with bounces to majordomo-owner.
Minor bugfixes.