- Other than multipart/mixed and PGP/MIME, Mutt should allow the user to
  specify what to do with other types of multipart messages (i.e., so a user
  can deal with S/MIME messages reasonably)

- option to not include attachments in replies

- handle message/external-body in some fashion

- handle message/partial reconstruction

- not possible to view the header of a single part message which contains
  something that requires a mailcap entry to view

- need to clean up the error recovery when running out of space when syncing
  a mbox/mmdf mailbox

- BODY struct should probably have a pointer to its corresponding HEADER
  struct.  this is needed for mh/maildir mailboxes so the correct pathname
  can be found.  Or perhaps all we need is a .hdr member of the STATE struct
  so that all of the MIME handlers can look up the corresponding HEADERs if
  need be?

- mailbox resync code for mh and maildir mailboxes

- fold long user-defined header fields

- history classes

- document honored environment variables

- add -v flag to pass to sendmail...

- ordered tag

- rfc822 parser needs to do something with the @host1@host2: portion of the
  route-addr

- command completion for `enter-command'

- new forward command to include first attachment in the editor and attach
  other attachments to the message

- adjust the names of *adr() and *adrlist() and calling routines for
  consistency

- mbox-hook entries should override $move?

- add a preserved flag to messages

- use an external lockfile(1) look-alike for dotlocking.
  This would remove the requirement for certain sites to
  install mutt setgid mail.
