* remove vclock_merge
 * remove vclock_destroy
 * use `server` instead of `node`
 * use `signature` instead of `lsnsum`
 * refactor vclock_from_string code

Add access checks in Lua iterators.

Add a owner for a user, use owner privileges to check
whether or not it's possible to drop a user.

Rebuild empty.snap, it can be used as bootstrap.snap to
fill the schema from scratch.

Update bootstrap.snap with an index on _user[2] (second
field in _user).

Conflicts:
	extra/rpm/tarantool.rpm.spec.in

t chec  # On branch stable

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

Conflicts:
	extra/rpm/tarantool-scl.rpm.spec

Conflicts:
	src/box/box.cc
	src/box/replica.cc
	src/iproto_constants.cc

Conflicts:
	src/box/replication.cc

Conflicts:
	src/lua/yaml.cc

Conflicts:
	src/box/box.cc
	src/box/replica.cc
	src/box/replication.cc
	test/unit/CMakeLists.txt

Make the new tests more stable.
Add a logger output, so that log is output to a file rather than terminal.
Make require_mod module test more robust.