Fix compilation (#9057)

monster_info doesn't have the heads() method, and even if it did, mon is
not a pointer here.
Remove an unused parameter (ChrisOelmueller)

Unused since 0.3-a0-224-g2931994.
Remove two more unused parameters (ChrisOelmueller)

Both have apparently been unused since 0.2 or so.
Select wall and floor tiles deterministically.

This is mostly so the view doesn't change randomly after level
excursions, e.g. after off-level jelly eating.

This required modifying the lua functions lev_floortile and lev_rocktile
to add a depth parameter; I didn't find any uses of those functions.
Remove two unused lua functions.

These were unused for 5 years (since commit 5500ccf).
Remove another unused parameter (ChrisOelmueller)
Move a function and make it static.
Make cowardly players not afraid of friendly neutrals

E.g. if you sacrifice courage, you are no longer terrified of Pikel's
slaves once they are freed.
Clean up some messaging/prompts for amulet of faith under Ru
Color Sacrifice Arcana mutations correctly.
Display the explosion radius in the Power Leap targeter.
Simplify cowardice
Fix some odd indentation (player-equip.cc)
Try to heal some vault scars from monster removals.

Admittedly, a bunch of this is abusing the new-ish torpor snail.

 * The Lair worms end now has torpor snails instead of fire drakes
   (instead of elephant slugs / etc) and yellow wasps instead of
   orange rats (instead of giant fireflies), with some placement
   adjustments to not make it too overwhelming. Still much harder
   than before, of course.
 * The Lair dogs and bears end uses a little more of each of its
   occupants (incidentally buffing the still-weak vault), instead
   of replacing the grizzly bears with hogs. It's a bit less variety,
   and I like the notion of getting some mileage out of hogs,
   but they are completely bizarre picks for the context.
 * One of Lom's vaults gets a trio ofshock serpents instead of
   a trio of lightning spires (instead of a trio of vapours).
   Eel statues aren't worthwhile for Pan.
 * An abyss vault gets a choice of a torpor snail or a giant leech,
   instead of a choice of a death yak or a giant leech (instead
   of an elephant slug or a giant leech). Some monster re-arrangements
   are done to compensate for this.
<theTower> fr add the roar of a wumpus to xom