Change top-level setq forms to defvar or defconst

Change top-level setq forms to defvar or defconst

Also collect some code onto fewer lines and reindent.
* lisp/play/dunnet.el (dun-visited, dun-current-room, dun-exitf):
(dun-badcd, dun-computer, dun-floppy, dun-key-level, dun-hole):
(dun-correct-answer, dun-lastdir, dun-numsaves, dun-jar, dun-dead):
(room, dun-numcmds, dun-wizard, dun-endgame-question, dun-logged-in):
(dungeon-mode, dun-unix-verbs, dun-dos-verbs, dun-batch-mode):
(dun-cdpath, dun-cdroom, dun-uncompressed, dun-ethernet):
(dun-restricted, dun-ftptype, dun-endgame, dun-rooms):
(dun-light-rooms, dun-verblist, dun-inbus, dun-nomail, dun-ignore):
(dun-mode, dun-sauna-level, north, south, east, west, northeast):
(southeast, northwest, southwest, up, down, in, out, dungeon-map):
(dun-objnames, obj-special, dun-room-objects, dun-room-silents):
(dun-inventory, dun-objects, dun-object-lbs, dun-object-pts):
(dun-objfiles, dun-perm-objects, dun-physobj-desc, dun-permobj-desc):
(dun-diggables, dun-room-shorts, dun-endgame-questions): Change
declaration to use defvar or defconst.
(dun-doverb, dun-vparse, dun-vparse2, dun-batch-parse):
(dun-batch-parse2): Omit the dun- prefix from arguments dun-ignore
dun-verblist.  Those are now constants and the byte compiler doesn't
allow defconsts in lambda lists.