- Add a target which determines which are the new distfiles in the DISTDIR
  directory, even if "old" distfiles are there.  The target should be able
  to move, copy, link or list those files.  For example: "dfdisk new CMD"
  where CMD is a random command (like mv, cp, ln or echo) to run on those
  files.

- Handle distfiles with bad checksums in disks.  The program should store
  a checksum of each file (SHA1) in the database and compare it against
  the one in the respective distinfo file before fetching it from that
  specific disk.  This means that dfdisk needs a way to know which distinfo
  file to look at...

- If a distfile appears in multiple disks and has different checksums,
  dfdisk should choose the right one.

- If a distfile appears in multiple disks, dfdisk should check if the disk
  in the drive has it before asking the user to change the media.

- Add a way to sort disks by preference when it comes to fetch files.
  Sorting them by date seems the most reasonable choice.

- Clean up the code and fix bugs, of course ;-)