Tinker with Abyss Spawns

1. Make non-abyssy things spawn less the deeper you go.
2. Spawn fewer small abominations deeper and more large abominations.
3. Reduce the rate of chaff (imps) with depth.

This is part of a longer term change to move the Abyss away from that place
you go to get stat drained and mutated by demons.
Merge branch 'master' into banish
Add Chimeras to the Abyss.
Purge '3' from the Abyss

Remove 3s (Chaos Spawn excepted) from the abyss.
End the tournament.
Improve a variable name.
Use the proper #define for berserk hunger boundary.
Use a COMPILE_CHECK instead of an ASSERT.
Remove some unused commands

CMD_EXAMINE_OBJECT, CMD_DISARM_TRAP and CMD_DESTROY_ITEM.
Fix a --test crash.

Somehow, it was broken by 0.8.0-a0-33-g1659bee, yet no one runs --test in
optimized builds, mostly because of makefile inadequacies.
Make -test NORETURN and easier to valgrind.
Actually init per-game seeds outside save transfers.
Even out the distribution by dungeon level of the food vaults.

Having looked at the code for chance_ tags in detail while enabling the
possibility of Hell/Pan/Abyss entry vaults, I realised that there were a
lot of problems with the way the food vaults were being handled; in
particular the CHANCE: tags attached to the vaults, despite being
different from vault to vault, didn't actually have the intended effect
of weighting the various vaults against one another.

I've decided to give the food vaults an even distribution over the
ranges which they can appear in (i.e. they have an even probability of
appearing on any given level in the ranges in which they can appear),
and WEIGHT them as intended against one another.

While I'm at it, this fixes a bug in grunt_ogre_cave which gave a 50%
chance of placing a two-headed ogre on D:7. It should have been a zero
percent chance.
Icon for durably-summoned monsters
Additional gargoyle base tiles (Xion350, 7631)
A couple more test cases.
"./crawl -test list" to enumerate available internal tests.

(We also got "canned" tests which are scripted using regular arena or game.)

Our Makefile deserves a good heap of profanity, as you can't recurse nor run
targets whose list of dependencies depends on something itself.  This is
because you can't just "make foo", you need to "make debug foo" or it will
f*** up your build, and the list of such required extra arguments is hard
to copy -- it can include compiler flags, EXTERNAL_DEFINES, etc.
Vastly shorten test/big/abyss_shift.lua, enable it by default.

Although, it doesn't do anything stress tests wouldn't catch.
Drop a token file into test/big/

git would remove the directory otherwise.
Move some boring test settings aside.

There's no reason to change them whatsoever; a particular test will set them
explicitely if it matters.