Clarify the decapitation clarification (|amethyst)

Again, wrt Hydra Form.
Adjust erik_ogre

Replace the rust devil with a goliath beetle, shift the vault
back down to its original depth, and remove a spoilery bit of
loot. Hangedman has plans for a more complete revamp, but this
should get it in better shape, I think.

Probably someone should have done this back when iron devils
were moved to 10 speed, but it's particularly relevant now that
they've been rusticated.
Improved algorithm to place multiple doors on long walls
Re-added layout_onion_city to Elf with better windows
Improved LUA primary_vault_dimensions function
layout-geoelf-castle-v2
Remove the hardcoded chain-spell force_more (minmay)

That's what rcfiles are for!
Remove the MR-immunity check for applying confusion to monsters

This check prevented MR-immune monsters from ever being confusable,
but this was a strange exception. Many sources of confusion already
check MR, in which case the check is redundant, and those that don't
(Zin recite, mephitic cloud, confusing touch) all have reasonable HD
checks.

This is a buff to Zin recite for MR-immune monsters with moderately
high HD like the Hell lords and named Pan lords, but the recite will
still need reasonably high invocations and high piety to have a good
chance of confusing or dazing these monsters. We can consider
shortening the duration based on monster HD if this change makes
recite too powerful.
Always weight formicid weapon acq towards 2H (PleasingFungus)

Regardless of Shields skill.
Reorder items in chardumps too (ChrisOelmueller).
Improve Shoals:5 decoy huts

By sometimes making one of them have a mimic rune instead! (Well,
it's really more like "sometimes have another rune hut and two
fewer decoy huts, but close enough...)
Double sword urand tiles
Various weapon/armour tiles (roctavian, 9031)
Spider sack tile (Bloax)
Fix rust devil corrosion (simmarine)

The code that checked for body armour went missing, somehow.
Add a temp param to holiness
New spell: Irradiate

Level 5 Conj/Tmut. Does heavy damage to adjacent foes (and
malmutates them, for flavour), but contaminates the caster; 2-4
casts will put you into yellow contamination. Design goal: play
around with contam mechanics and tmut/contam interactions & add
a neat tm support spell.

Currently in the Book of Alchemy and the Book of
Transfigurations. (Ice Form has been moved from the latter to the
Book of Ice, per Grunt's suggestion.)
Rework monster malmutation

Now that it's an actual effect that will actually appear in games
(irradiate), it should probably be made sane.

Changes:
- Action speed penalty (-1/stack) removed.
- AC penalty increased to -4/stack. (From -1/stack.)
- Damage penalty removed, for gross crimes against good coding.
  (Was -10%/stack, to max of -50%).
- HD penalty added; -10% stack, to max of -50%. Applies after
  draining, to avoid undue synergy.
- Effect made temporary; celebrate, Beoghites!
Fix hardcoded "hands"

In the Hellfire equip message, the confusing touch expiration
message,  and the finesse activation & experiation  messages.
(Oddly, the expiration messages handled MUT_MISSING_HAND, but
not felids/octopodes.)

Someone desperately, desperately needs to generalize the verb
conjugation ("hands slow" vs "hand slows") stuff - there must be
a dozen place that it pops up in the code, thanks to missing
hand...
Add a missing image (checkers)