- Cleaned up documentation, with a real man page.
- Support for clusters larger than 16K.  This would require changing
  a lot of the SYSLINUX internals so we can read partial clusters;
  change the current "cluster pointers" to become
  "cluster:sector pointers".  (32K may be doable.)  Microsoft
  documentation claims that 32K is the maximum legal value although
  "some versions of some systems allow 64K".
- EBIOS support.
- FAT32 support?
- Support initrd that span multiple input media?
- Support a small set of DOS system calls for COMBOOT images?  (Serial
  console support makes this particularly desirable.)
- PXELINUX still needs work.