Switch Ru's muting effects to antimagic

Mute was being applied to creatures that can't be muted (demons, dragons)
and also mute just didn't limit enough cases. This switches the effect
to antimagic, adjusts the messages, applies proper checks for valid
targets, and greatly increases the duration because antimagic isn't
absolute.
Improve Ru retaliation messages.
Improve loot for one stingy Lair end vault (crate)
Don't crash when swapping an ally onto a shadow/spider trap.

They would trigger the trap before the player is moved into place,
potentially summoning something on top of the player's location.  See
for example:
  http://crawl.akrasiac.org/rawdata/FACE/crash-FACE-20141228-180029.txt

There is still a crash here, which is more difficult to solve.  If you
were standing on a toadstool (atop the trap) and swap with a wandering
mushroom, the mushroom will again trigger the trap before moving the
player.

Related, if you are atop a toadstool and the mushroom is on a trap,
then swapping with the mushroom triggers the trap twice: once for
the toadstool and once for you.
Don't crash when swapping mushrooms onto toadstools on traps.

Also, don't double-trigger traps when you and a toadstool swap with a
mushroom onto the trap.

These are the two cases mentioned in the previous commit.
Add some XXX-rated comments
Brace
Fix book naming

This is very silly...
Erp
Don't turn all items into books
Fix a sign warning.
Merge branch 'master' into evoker-god
Rework Pakellas gifting.

It's much more rare, less weighted towards wands, and (if you aren't a
felid) guarantees a rod as your first gift.

I'm not completely sold on the latter point, but considering most of the
abilities are geared towards rod use, I think it makes a certain degree
of sense.
Step down Quick Charge effectiveness.

It starts falling off in effectiveness after 33% charge capacity,
hopefully turning it into more of a quick fix than the fountain of
recharging it was before.