* fix_date.sh

  Add a 'Date:' header to the selected email(s) when such header is missing.
  The correct date is guessed from other headers that contain timestamp
  information or from the file or system date as a fallback. The order or
  preference for the date value replacement can be changed by editing the
  script.
  This script can be used to fix messages that show non RFC-compliant Date
  headers as well.
  X-Original-Date is always added too, to keep track of the original value
  if any.
  Date: header is not overwritten unless you use the --force switch.
  X-Original-Date: header is overwritten.
  Non RFC-compliant dates can be overwritten using the --rfc switch. Use
  --strict to use strict RFC matching patterns for date values.

  WORKS ON: selected message(s)
  
  COMMAND: fix_date.sh %F
  
