Remove the Vorpal special case for branding unbranded weapons.

It didn’t do anything interesting. Otherwise, rebranding branded weapons
would not be randomized either.
Some scroll generation weight clean-up

Move depth_mod < 7 scrolls to depth_mod < 4, divide item weights by
roughly ten.
Disable layout_big_grid

It wasn't really interesting, just making a large amount of wide open
spaces.  Basically anything good about the layout can be replicated by
the city layouts or forbidden_donut.
Remove an ancient comment
Beogh/Lucy invo icons
Chei invo icons
Yred invo icons
Let Cherubs buff higher HD holies (wheals)

Hopefully acutally letting Cherubs use their special ability will show
if they should be removed or not.
Fix non-cherub battlecries working on higher-HD monsters
Change Mark's status light colour to LIGHTRED.

LIGHTMAGENTA is a colour we use for positive status effects such as DMsl
or cTele, so you can completely miss that you're Marked if you have some
of those up.

Also adjust its long description to be more clear.
Changelog through 0.15-a0-985-g23b1178.
Don't waste time casting Animate Dead, usually.

If there's a visible corpse nearby, the behaviour is the same. If
there are no items, 'z' should not waste time/MP, while you can
still force a cast with 'Z', so that you can animate corpses that
are below other items and you can't see with ^X.

Sadly, this doesn't really work for Yred since there's no way to
force a use of an ability the way there is with a spell.
Don't trigger PbD on gold corpses
Trog invo icons

BiA isn't done because I still haven't decided what summons should look
like.
Paper over a crash (#8587).

This gets the game to load, but the underlying issue is still at large.
Make no device heal a normal 3-level mutation.
When flagging Gozag-detected gold, assert that there's an item there.

Should catch the crash in #8584.
Really fix Gozag gold detection (#8584).

It was moving the wrong item to the top of the cell - I wanted
item_def::index(), not item_def::link.

Also, if the gold was the second item on the cell, it would get missed, and
if more than one identical item was being generated on the same tile before
and after the gold, it could also get missed.
De-float some code.
Trigger shoutitis on seeing enemies, not randomly (dck).

This should make it more relevant.