Add rope implementation based on AVL trees.
Add unit tests.

Conflicts:
	mod/box/box.lua
	test/box/lua.result
	test/box/lua.test

https://bugs.launchpad.net/tarantool/+bug/1035286

https://bugs.launchpad.net/tarantool/+bug/1034912

Sync the WAL at close time.
Fix a race condition between wal_schedule and ev_schedule
this revealed.

A cancelled fiber could get scheduled by wal_schedule.
Do not allow to asynchronously cancel a fiber which
is a part of WAL scheduler queue.
Add a test case.

implemented (hexademical output needed)

(https://bugs.launchpad.net/tarantool/+bug/1032582)

(https://bugs.launchpad.net/tarantool/+bug/1032583)

Fix debian/copyright (closes lintian warning).

[FreeBSD]: port files.

Implement blueprint
https://blueprints.launchpad.net/tarantool/+spec/wal-mode-none

Add wal_mode = none setting.
It's possible to chagne wal_mode without restart.

When wal_mode = none, we don't write to WAL.
It's still possible to take a snapshot.

Replication and hot standby are currently not
operational in this mode.

End the copyright madness. Tarantool authors maintain a shared
copyright on the code base. Remove individual copyright (c) from
specific files and put a single AUTHORS file in the project top.

A fix and a test case for Bug#1030856
'box.update() doesn't support subtract, contrary to the user guide'

Add subtract support, add a test.

Conflicts:
	mod/box/index.m

A fix and a test case for Bug#911641
"box.fiber.sleep() works incorrectly if a fiber is attached".

Use symmetric scheduling for attached fibers. This allows box.insert(),
box.update(), box.delete() box.fiber.sleep() in an attached
fiber just the same way as in a detached one.

Add tests.

Now it's possible to resume() a fiber created in another fiber.

Conflicts:
	mod/box/tree.m