Generate the directory list for the subject line, and revamp how we compose the subject line.
Generate the directory list for the subject line, and revamp how we
compose the subject line.

* hooks-scripts/mailer.py
  (mail_subject): removed. MailedOutput.__init__ handles this now.
  (MailedOutput.__init__): compute the directory list for the subject
    line and then compose the bulk of the subject (i.e. no prefix)
  (MailedOutput.start): new method to set up the .to_addr and
    .from_addr attributes for use in mail_headers()
  (MailedOutput.mail_headers): revamp composition. use the new from/to
    address attributes and compose the previously generated subject
    with the group-specific prefix. add \n after the headers.
  (SMTPOutput.start): toss (broken) assignment of .to_addr and
    .from_addr; it is now in the superclass. no longer need to write a
    newline after the headers.
  (PipeOutput.start): call the superclass method and use self.to_addr
    for the destination rather than fetching ourselves. no need to
    write a newline after the headers.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion