Merge remote-tracking branch 'origin/stable'

Conflicts:
	include/fiber.h
	include/mutex.h
	src/admin.cc
	src/admin.rl
	src/box/box_lua.cc
	src/box/request.cc
	src/box/txn.cc
	src/coeio.cc
	src/coio.cc
	src/fiber.cc
	src/ipc.cc
	src/iproto.cc
	src/log_io.cc
	src/lua/bsdsocket.cc
	src/lua/init.cc
	src/lua/session.cc
	src/memcached-grammar.cc
	src/memcached-grammar.rl
	src/memcached.cc
	src/recovery.cc
	src/replica.cc
	src/replication.cc
	src/say.cc
	src/session.cc
	src/tarantool.cc
	src/util.cc