* mymalloc.h: always allocate one extra byte, since some malloc's

* mymalloc.h: always allocate one extra byte, since some malloc's
  return NULL for malloc(0) or realloc(p, 0).  (This should be done
  differently than wasting one byte, but alas...)
* Moved "add'l libraries" option in Makefile to an earlier place.
* Remove argument compatibility hacks (b) and (c).
* Add grey2mono, dither2mono and mono2grey to imageop.
* Dup the fd in socket.fromfd().
* Added new modules mpz, md5 (by JH, requiring GNU MP 1.2).  Affects
  Makefile and config.c.
* socketmodule.c: added socket.fromfd(fd, family, type, [proto]),
  converted socket() to use of getargs().