New Vaults layout by infiniplex.

This is a massive change to the branch. It causes the levels to be made up
of a basic layout, filled with subvaults (drawing from a pool of several
hundred). See the following link for more detail:

https://crawl.develz.org/mantis/view.php?id=6059
Shorten Vaults to 5 levels.

This is done for a few reasons:

  1. It's been discussed for quite a while now.
  2. With the redone layout, now seems like a good time to make this change.
  3. The new layout is much denser in terms of XP and Loot. Cutting the
  branch to 5 levels compensates for this (actually overcompensates a bit,
  at least in terms of XP).

This also increases its absdepth by 3 (keeping Vaults:5 at the same depth as
the old Vaults:8), and moves the entrance slightly deeper in the Dungeon.
Unique depths have been tweaked. Crypt and Blade are unchanged, though maybe
they should get their depth boosted too.
Actually add the new Vaults layout.

Whoops.
Remove a file added by mistake in the last commit.

Didn't realize I had that sitting around.
Add a 'uniq_lab' tag to the labyrinth entrance vault.

Needed for the new Vaults layout, for subvault purposes.
Remove some commented out vaults.
Adapt serial_hangedman_research to be placeable in new Vaults layout.

The old incarnation still works as expected; the serial vault just
happens to be placeable in the new layout as well.
Re-tag/adapt some minivaults removed from Vaults for new vaults layout.

These are the ones that fit into the layout somehow. Some may not end up
working very well (minivault_9, I'm looking at you, but what would
Vaults be without a door vault now and again?), but testing should help
us to figure that out.

This also prevents attempting placement of (mini)vaults in Vaults.
Rejig wall types in Vaults to account for new depth.

V:1 has a 2/3 chance of being stone walled, and V:2- have a (depth - 1)
in 5 chance of being metal (otherwise being stone). The old chance for a
crystal layout on V:7-8 now applies to V:4-5.
Fix Trove-related Lua errors in the Vaults layout.

The chance_trove vaults didn't have a Vaults depth assigned, so the
subvault calls in the Vaults layout would not be able to find a subvault
for it.
Tag magic_research subvaults with no_rotate and no_{h,v}mirror.
Merge branch 'master' into new_vaults_layout

Still need to deal with secret doors - a couple of the subvaults still have
them.
Desecretize the layout_vaults subvaults.
Replace some cases of no_tele_into with no_rtele_into.

If you want to teleport into a sealed glass box, it's your fault if you have
no way of escaping. Blocking random teleports is sufficient.
Do not attempt to place serial_grunt_rogues_gallery in Vaults.

With the new layout, this serial vault doesn't work here. Serial vaults do
work in the branch, but they need to be designed with it in mind.
Actually fix Xom effects lasting less than a turn

Probably should've caught this when increasing their duration before,
oops.
Buff Ereshkigal.

She was the weakest hell lord, aside from Geryon (although even he had more
HP than Ereshkigal). The following changes have been made.

HP: 250 -> 350
Melee: Gain XP-drain melee attack (compensate for loss of bolt of draining)
Spells: Loses bolt of draining, gains silence. Minor healing (emergency
        spell) replaced with major healing.

She still lacks direct killing power, but these changes should make her a
very nasty summoner (her summons are immune to silence).

Bolt of cold was chosen over bolt of draining because it is a more dangerous
spell, and the same resist covers both torment and draining. Her overall
abilities still keep the "negative energy" theme, in my opinion.

A note about the HP: Eresh has good EV, but this isn't enough. She simply
dies too quickly. All of the other hell lords have extremely good defenses
and high HP... there is no reason for Eresh to be so weak.
Adjust the unique Pan lord entry messages

Make the flavour message more noticeable and explicitly name the Pan
lord.
Let soul eaters eat souls.

This gives them the drain life spell. One of their spell slots is
SPELL_MELEE, since without this, things get a bit too spammy. Damage is
similar to smiting, so it's not a huge buff. They still belong as '3' type
demons.

I figure we have enough melee enemies with AF_DRAIN_XP, and soul eaters were
one of the more boring 3's because of that. Also, drain life seems fitting
for a monster with this name.
Attempt to repair serial_hangedman_research placement in Vaults.

I'm not sure if this does it - there might still be a couple of subvaults
placed wrong. I had trouble getting more than a vague description for this
bug. Apparently Grunt knows something about it, so he should have a look at
this.