Purge some racial missiles code.
A new throwing missile, tentantively named "tomahawk".

The name is somewhat problematic, as real tomahawks were fit for melee
(just like hand axes...).  It's mostly because a few bailey_axe vaults
want something that resembles an axe, but I'd rather axe or redesign
those vaults than have them block better alternatives.

The balance purpose is to have something between darts (damage 2) and
javelins (damage 10), for use by orcs, orc warriors and merfolk.
Change hand axes of returning in baileys to tomahawks.
Generate monsters with tomahawks rather than throwing weapons.
Mark all weapons as non-throwable.  Can still be fumble-thrown.
Purge obsolete code for quivering weapons.
Remove the returning brand for weapons.
Purge a small part of monster thrown weapon AI.
Purge the code for throwing (rather than fumbling) weapons.
Always id weapons on wield.

Calculating pluses is a matter of hitting anyone several times and using
a script to analyze the results.  Plus, this is what armour does already.
Macabre Finger Necklace

A warding amulet that provides you with another ring slot.

I rewrote some of the jewellery code, but never re-added the
TOUCH_UI code I removed in _prompt_ring_to_remove. Note that octopodes
never had TOUCH_UI code for their jewellery in the first place. This
should probably be looked at.

Also, the player dumps do not show the amulet
ring on the top, but I do not consider this a problem.
Drop capitalization from the macabre finger necklace.
Fix the amulet ring not showing on ".
Let monsters pick up Elf:$ loot

Unlike loot in Ziggurats, there's at least a slight chance that the
monsters here can get some relevant use out of the equipment (rods,
randart weapons and armour, etc).
Make Sticks to Snakes only work on missiles

Working on weapons makes for a more awkward interface and the possibility of
accidentally destroying things. As a level 2 spell its power level is fine
with just missiles being permitted.
Don't generate Lehudib's crystal spear the unrand.

Without returning, it doesn't work anymore.
Shorten the abyssal generator depth to 32 bits (fixes an infinite loop).

A good enough fix would be to re-cast the depth to unsigned during
unmarshalling so it doesn't get sign-extended before putting into an
uint64_t variable.  Bits above 32 can't be ever used, though -- even
bits over 31 hardly ever do (initial value is < 0x80000000 but increases
with time).
Fix a warning.
Two new quotes.
Some documentation for the abyss bot.