- Implement "FEAT" and "OPTS" commands.
  - When necessary, the front end will pass options to the backends
    using $OPTS_whatever.

- Tests:
  - u+s g+s +t permissions on listings
  - LOGREQUESTS on/off
  - LOGRESPONSES on/off
  - \377 escapes on output
  - CWD into various mode directories
  - RETR from/STOR to various mode directories

- Write a twoftpd log tailing program to output timeout stats and the
  like.

- Add IPv6 support.

- Build-in support for recursive retrieval producing a tar file internally.

- Look into spying on the status of the servers:
  - exporting status through environment or modifying the command-line
  - get pids by looking for children of tcpserver
