Fixes gh-47.

Update test results to be more deterministic.

Conflicts:
	src/box/space.cc
	src/box/tuple.cc
	test/wal/oom.result

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.

Add comments, update the manual.

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.

Fixes gh-45.

Conflicts:
	src/recovery.cc

Conflicts:
	test/box/lua.result
	test/box/lua.test
	test/lib/sql_ast.py

Fix https://github.com/tarantool/tarantool/issues/44

Provide open_memstream() implementation for system which
miss it (Mac OS X).

Conflicts:
	src/lua/init.cc
	test/box/lua.result
	test/box/lua.test

A copy-paste implementation of print(64 bit number)
used to add an extra newline at the end of printed string.

Allocate slab arena in shared memory to reduce pages splits during
snapshotting.
Adaptation of patch made by Yuri Nevinitsin @nevinitsin.

Conflicts:
	test/box/alter_limits.test.lua

When looking for the next xlog to recover from, take
into account gaps in LSNs which may occur due to wal_write()
failures.

Add test coverage for create/drop space and error injections.
Add cleanup to alter_limits.test