Cleaned up some messages, added a check to remove a leftover popd file

Cleaned up some messages, added a check to remove a leftover popd file
from /var/mail, added a routine to delete the removed user's files
from /tmp, /var/tmp, & /var/tmp/vi.recover, and added code to kill any
running processes owned by the removed user).  I've also added a flag
for non-interactive execution, cleaned up the man page, and adjusted
my address.

Submitted by: ghelmer@cs.iastate.edu (Guy Helmer)