fix snap_io_rate_limit handling
shared-arena: shared arena, closes #36
Allocate slab arena in shared memory to reduce pages splits during
snapshotting.
Adaptation of patch made by Yuri Nevinitsin @nevinitsin.
replace fdatasync() to open(O_SYNC)
fix: do fdatasync() only when snap_io_rate_limit bytes written
Reformat --format tarantool for one-line input
shared-arena: review fixes, slab_q moved to separate file.
Add support for custom error codes in box.raise()

Fix https://github.com/tarantool/tarantool/issues/44
Merge branch 'stable' into odkl-fix-snap-io-rate-limit
gh-45: review fixes
shared-arena: make arena snapshot-version aware.

On snapshot, increase snapshot version id (u32),
save current snapshot version within a tuple.

On tuple free, check if tuple version is equal to current
snapshot id, if so do direct free, otherwise append tuple
to the delayed free list.
gh-47: (shared-arena) review fixes

Add comments, update the manual.
Merge branch 'shared-arena' into stable
gh-47: update wal/oom.test

Tuples are got a big bigger with shared-arena patch (4 bytes
per tuple overhead).

So we exhaust the current arena in out-of-memory test a bit
faster than before.
opentar-48, opentar-52: support old config layout.
Merge branch 'tc-tarantool-newf' into stable
Merge remote-tracking branch 'origin/stable' into saving-remote-sockaddr-to-WAL
gh-35, opentar-45: review fixes

Remove get_socket_addr(), use existing sockaddr_in
to save in the cookie.