#vanquished (trunk only)

Add #vanquished command to show the vanquished monsters list during
play.  At present it's only available in wizard mode.  Slash'em has it as
a regular mode command, and I found it handy sometimes:  when I managed to
kill an unfamiliar monster, I could immediately get an idea of how the game
ranked its difficulty compared to other monsters.  But having this command
available might encourage extinctionism.  On the other hand, it might stop
some existing extinctionists from cycles of save+copy+restore+quit to view
disclosure data for their current game.

     This also makes merging the wizard mode extended commands into other
extended commands be more robust.  It will panic instead of going out of
array bounds if someone adds entries to debug_extcmdlist[] without also
expanding extcmdlist[] to make room.

include/extern.h

@@ -628,6 +628,7 @@ E void VDECL(panic, (const char *,...)) PRINTF_F(1,2);
 E void FDECL(done, (int));
 E void FDECL(container_contents, (struct obj *,BOOLEAN_P,BOOLEAN_P,BOOLEAN_P));
 E void FDECL(terminate, (int));
+E int NDECL(dovanquished);
 E int NDECL(num_genocides);
 E void FDECL(delayed_killer, (int, int, const char*));
 E struct kinfo *FDECL(find_delayed_killer, (int));