Fix bugs in spawner child handling, performed at shutdown:
- shutdown children more portably
- remove races with lost SIGCHLD
- do not self-terminate when doing kill(0, signal)
(sending signal to entire process group).

Clean up custom_proc_title handling and fiber names.

Write mehtod in the TarantoolConnection class was updated.

Allow fiber_io_* on an fd which is ! fiber->fd,
and remove inbox2sock/sock2inbox in replication.

Fix a merge error (remove debug print).

Write method in the MemcachedConnection class was overlapped for correct
work with memcached protocols. Memcached tests was cleanupped.

Remove one memory leak in recovery_follow_remote.

Rename hot_standby back to local_hot_standby. Let's
not break compatibility without a strong need.

Merge replication_source_ipaddr and replication_source_port
to a single variable, replication_source, to be able to
provide a list of sources in future.

Update comments in the configuration file.
Remove custom proc title for replication, use custom_proc_title of
the main process.
Renames.

the tarantool logger process was changed from tee to cat.

Conflicts:
	cfg/tarantool_box_cfg.c
	cfg/tarantool_box_cfg.cfg
	cfg/tarantool_box_cfg.h
	cfg/tarantool_feeder_cfg.c
	cfg/tarantool_feeder_cfg.h
	core/exception.m
	core/fiber.m
	core/log_io.m
	core/log_io_remote.m
	include/fiber.h
	mod/box/box.h
	mod/box/box.m
	mod/box/box_cfg.cfg_tmpl
	mod/box/memcached.m
	mod/box/memcached.rl
	mod/feeder/feeder.m
	test/box_replication/common.result
	test/box_replication/suite.ini
	test/lib/admin_connection.py
	test/lib/box_connection.py
	test/lib/server.py
	test/lib/sql_ast.py
	test/lib/tarantool_box_server.py
	test/lib/tarantool_connection.py
	test/lib/tarantool_feeder_server.py
	test/lib/tarantool_server.py

Make sure we do not try to modify data in
read-only mode via memcached port.

Update test results, and the Python client.

Blueprint 'Make memcached protocol an alternative, not a replacement':

Blueprint was implemented. Memcached now can work
in presence of RELOAD CONFIGURATION statement, even if it
changes a replica to master or a master to replica.

'memcached' configuration file option was removed.
Instead, two new optinos were added:
- memcached_port - optional, default 0, if set, specifies
which port speaks memcached protocol.
- memcached_expire, boolean, which defines whether or not
we run expire on memcached namespace. If not set,
we simply support the protocol, but ignore TTL and never
expire the keys.

Original memcached test was ported to tarantool testing environment.
cas test was disabled, because tarantool has a non-critical bug (in
concurrent environment cas operation can return 'SERVER_ERROR' instead of
'EXISTS')

`sptree_str_t_find' in `index_find_tree'.

`sptree_str_t_find' returns `struct tree_index_member' rather than
`struct box_tuple'.

Don't read field data in case of zero size.

Handle close replication socket on oposite side was added.
box replication test was updated.

Missed inotify even in the replicaor handler process was foxed.
replicaor_init was splited on two function:
  - replicaor_prefork -- create replicaor spawner process;
  - replicaor_init -- initialize replicaor fibers in the main tarantool
	                  process.

Test and test configuration files in box_replication soute was
clenupped and updated.

We modify memcached code quite often,
and asking ragel to regenerate .m from .rl file
every time .rl file changed was tiresome both
for revision control and for code reviews.

Leave in memcached-grammar.rl only memcached_dispsatch(),
which is generated by ragel, and everything else
move to memcached.m. This should lessen cases
when we have to re-generate memcached-grammar.m.

This patch doesn't produce any code changes,
only moves the code (and cleans up include
files at start of memcached.m).

Remove compilation warnings about unused variables.

Make sure Release and RelWithDebugInfo do
not include -Werror - we don't know compiler version
at the client and shouldn't plant time bombs for him/her.

box replication test was updated:
 - common test was splited on three test:
    * hot_standby test -- check replication from hot_standby server
        * swap -- this test iteratively swap services roles (master to
                  replica, replica to master)
        * consistent -- this is test check replica data consistent
 - unused configuration files was deleted.
 - get_param method to tarantool_to_slave

Replicator was updated:
 - bind replicator poer strategy was changed.
 - terminate child routine for spawner process during exit was added.
 - handle EPIPE error was added to client handler process.
 - remote_hot_standby was deleted.
 - local_hot_standby was renamed to hot_standby.
 - sender_send_sock function was fixed.
 - I/O event processing in replicator fibers was updated.

Fiber:
 - fiber_io_* functions now public.

Reorder and simplify calls to box_enter_master_or_replica_mode()
in mod_relaod_config().

Move recovery_stop_remote() to log_io_remote.c, where it belongs.
Remove now unnecessary recovery_start_remote(),
use recovery_follow_remote() (same thing) instead.

mode

Reorganize the code responsible for entering/leaving master mode.

Remove remote_recovery_restart, add remote_recovery_{stop/stop},
make sure we know what to do - start or stop recovery.

Move 'remote_recovery' to struct recovery_state.

Remove an extra parameter to recover_follow_remote,
it's always the same currently.

Fix a coding error: supplying 0 watermark to kh_init(fiber_registry)
lead to almost constant kh_resize (on every kh_put after a kh_del).