A pre-requisite patch for Lua stored procedures:

in some cases, it would be nice to create a Lua context
in connection and destroy it when a connection ends.

Unfortunately, right now fiber connections are stateless:
there is on fiber constructor, destructor, or non-global fiber
state.

Change that by introducing fiber->pool, an allocation
pool in which memory lives till a fiber is destroyed
or becomes a zombie.

We already have fiber->pool, which life cycle is different:
it is created when a fiber starts, destroyed when a fiber
ends, but also is garbage-collected once in a while.

Rename this pool to fiber->gc_pool, to allow using
name 'fiber->pool for something else.

This patch only performs a rename and does nothing else.

Touch the generated files at configure
to avoid unnecessary rebuild.

Fix out-of-source builds and tests (test/box/protocol.test
was the main offender).

In DELETE, support flag BOX_RETURN_TUPLE.

A community request from Alexandre Kalendarev.

In the new DELETE (21) command, one can specify
delete flags. If BOX_RETURN_TUPLE is set, return
the old (deleted) tuple to the client.

Update doc/box-protocol.txt to reflect the new
(21) DELETE and its extended response format.

- token_is_identifier function was changed;
- TarantoolStreamReader was updated;
- admin connection in tarantool console client wax fixed.

tarantool preprocessor routine was changed:
 - Now 'exec obj ...' command will translate to obj.execute(...);
 - New command 'send' and 'recv' was added. 'send obj ...' and 'recv obj
   ...' will translate to 'obj.send(...)' and 'obj.recv(...)'
   respectively;
 - New command modifiers 'silent' and 'verbose' was added. Verbose
   (silent = False) value is default.

Tests - box, box_big, box_memcached, box_replication was updated.

Update the user guide with new links to configuration file,
and changes to replication configuration parameters, now that
feeder-in-core has been pushed.

Add lua generated files to .gitignore

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).