Upgrade Mennas's Confusion

To Mass Confusion; a better fit for the Recite theme that it's
riffing off of, and also much more likely to do something at the
depth he appears.
Changelog through 0.16-a0-1503-gb61f0ef
Overlooked changelog entries
Turn Form*::instance into a static member function.

This avoids having to define static const members outside the class, and
would make it easier to be thread-safe should we need that in the future.
Disallow copy and assign using explicitly deleted methods.

If compiling as C++11, that is. Otherwise continue using declared-but-
undefined methods.

Unfortunately, this breaks compilation with Visual Studio 2012, since
explicitly deleted methods weren't supported until 2013.  We could
preserve 2012 building with an extra check for MSVC version, but someone
who uses MSVC will have to do that.
Document autofight in ?? (vimpulse, PF)

Sadly, there is no way to make this match the user's actual key
binding, because autofight is implemented as a macro rather than a key
binding.
Cherry-pick the 0.15.2 changelog

And remove the duplicate entries from the 0.16 section.

(cherry picked from commit 9b7472d89d3a56797f2d1182218daf851657f63c)
Don't crash when a dryad following you considers awakening vines.
Make draining clouds check multiple pips of rN, not just the first

Negative energy clouds should be more like bolts of negative energy
and less like the impure, incidental checks of pain, vampirism, or
drain speed. It is a tiny buff against monsters with only rN+, but
those are exceedingly rare equipment-based circumstances anyway.
It does also mean it's harder for players to waltz through the clouds,
but that trick already was heavily buffed with the loss of item
destruction on freezing / flaming clouds, so whatever.
Update options_guide.txt.
Use phi for runes in char_set = unicode too (Alpha__).
Don't crash when placing MONS_DRACONIAN
Set monster gods correctly again.
Document lose_piety and dock_piety.
(LogicNinja) Fix nopiety troves with amulets of faith.

Previously, they took too much faith and generally caused the player
to be excommunicated; this change uses the correct piety-loss function
so they don't cause excommunication anymore.
Double Ephemeral Infusion's health restoration, halve its duration.

The results here are intended to make the temporary HP spike spell
more noticeable in its effects, aiding blood saints in helping
their allies (especially since they can damage their allies)
and thus giving them something besides top conjurations.

Also, remove a redundant tracer check.
Rot reform

Chunks are now handled in the same way as potions of blood; all
chunks of an 'edibility class' (edible, poisonous, necrotic,
mutagenic, profane) stack together into a homogenous meat slurry,
and rot individually.
Disable spraying chunks of forbidden meat

To avoid circumventing food conducts with /disint or IOOD.
Shift food conducts to purely butchering

To cut the gordian knot of dealing with persisting conducts on
chunks.

Remove penalties for eating chunks; sharply increase the penalties
for butchering forbidden corpses. (They were previously pretty
toothless.)
Remove rotting chunks & corpses & coagulated blood

Mostly wasted players timed with marginal flavor benefit. Also,
complicated the code enormously.

Ghouls now get the same benefits from normal chunks that they did from
rotting chunks, before. (Unless I missed something.)