Resync debian/changelog entry.
  Build with pkg-config.
  Stored press-mentions for posterity.
  Stub .signature support.

  We now call the on_signature function when composing mails,
 which will return the approriate text.

  This updates #40
  Replace get_signature() with a real implementation.

  This works usefully :)

  Closes #40
  Updated select_maildir() to return a boolean.

  This closes #39.
  Reorder functions alphabetically.
  New primitive: send_email()

  This function now works; sends a mail and writes a copy to the
 sent-mail folder.

  Closes #38.