Combine WebTiles messages and send them together

Idea being avoiding lag caused by TCP ACK etc. Crawl process provides
messages like always, but also sends a special flush message to the
WebTiles server that causes them to actually be delivered.
Remove debug print statements.
Disable WebSocket compression on Opera
Mention the manual and the FAQ in release docs.

They failed at least twice in the past.
Don't speak about "mana" to the player (rchandra)
Add a way to disable Webtiles compression on the client side.

Run $.cookie("no-compression", true) and reload the page. There's no
UI for it.
Tutorial fixes

Some missing </foo> tags, and lots of spacing fixes - it looks
like wrapping tutorial.txt has a tendency to break spacing. Should be
all fixed in console at least.
Fix some hints mode messages

There are almost definitely more that need fixing still!
Changes to the changelog.
(cherry picked from commit 5a01fa20208edc4a16969ae2b6f5fc80953b0f73)

Conflicts:
	crawl-ref/docs/changelog.txt
Fix typos in changelog.
(cherry picked from commit a9ee58fbd0a249850f30c236bca8aede5718bfed)
Update changelog through 0.13-a0-557-gcd82a8c.

Some of these entries could probably use a bit of tuning.
Ensure abyss shifts with the Orb don't crash the game.

Abyss shift indirectly used player:shiftto(), which called
set_position() instead of moveto(), thus bypassing the code for
resetting the orb position; this moves the relevant code to
set_position() so that it's always called.
Changelog for 0.11.2
(cherry picked from commit 87fb58c09b18d503fa29cd4a032a94a1b0d5e85a)

Conflicts:
	crawl-ref/docs/changelog.txt
Make sure to crash properly if a write_message vsnprintf fails.
Simplify.
Comment for Brendan's vault "Library of babel".
Make lava/water overflow altar more likely.

It is an overflow with a reasonable obstacle (flight, blinking will get you
in). No need to make it artificially rare.
Make helmets magenta.

While terminals that display dark grey as black have hopefully died out,
there's some confusion with out-of-LOS.  Also, lets better reserve darkgrey
for useless items only.
Make axes magenta.

Same reasons as helmets, also, magenta was not even used by anything (other
than two fixedarts).
Move unrands out of mundane colours.

Glaive of prune and Leech are new, but even before, robe of Misfortune
shouldn't have masqueraded as a cap, and hat of the Alchemist shouldn't
look like a mundane hat.