Rot reform

Chunks are now handled in the same way as potions of blood; all
chunks of an 'edibility class' (edible, poisonous, necrotic,
mutagenic, profane) stack together into a homogenous meat slurry,
and rot individually.
Disable spraying chunks of forbidden meat

To avoid circumventing food conducts with /disint or IOOD.
Shift food conducts to purely butchering

To cut the gordian knot of dealing with persisting conducts on
chunks.

Remove penalties for eating chunks; sharply increase the penalties
for butchering forbidden corpses. (They were previously pretty
toothless.)
Remove rotting chunks & corpses & coagulated blood

Mostly wasted players timed with marginal flavor benefit. Also,
complicated the code enormously.

Ghouls now get the same benefits from normal chunks that they did from
rotting chunks, before. (Unless I missed something.)
Guard against malformed timers

Probably we should be able to catch/prevent this earlier...
More rot error-handling
Deprecate potions of coagulated blood
Fix compilation.
Replace Draconian Breath on old draconians.

See for example:
    http://dobrazupa.org/morgue/stainable/crash-stainable-20141021-045702.txt
Fix a bad assert
Don't let pan lords try to cast DFireball

Since they can't, yet!
Refactor can_ingest, rename to can_eat.

I assume it was called can_ingest because it was supposed to be used
for potions too, but that just added needless complexity...
Remove some rotten code.

Yuck!
Deduplicate.
Fix compilation.
Refactor Tiamat colour-shifting.

As a consequence, red draconian Tiamat is now light red, like other
red draconians.
Let Tiamat be yellow, mottled, or pale.

Maybe she should be allowed to be grey too? It's a bit more boring since
there's no breath.
Remove unused chunk icons
Remove support for auto_drop_chunks = rotten
Update documentation