Offer rotten chunks first to those who can eat them.

Since rotten chunks pose no negative side effects to saprovores, don't
disfavour them when offering to eat chunks.  The end result is that
rotten chunks will be offered first, since they are by definition less
fresh than unrotten ones.
Wrap level-building docs to 80 chars.

I left a few sample map lines that went slightly over the limit.
New Lua methods you.ability_table(), you.spell_table().

These return a table with letters as keys and spell/ability names as
values.  Previously, finding the spell on a given letter required
cross-referencing the results of you.spells() and you.spell_letters().
Now it is as simple as  you.spell_table()["a"]
Don't double the tiles for Mara and rakshasas.

There might have been an info leak here, too.
Purge two unused bat tiles.

Ice bats use new simulacra tiles (blue rather than white).
Fruity bats have been given the axe.
Purge unused generated vine statue tiles.
Fix skeleton toad tiles not being used.
A script to find tiles not used by any tiledef.
Remove Pan.

Yes, once again.