Fix a bug when Lua transaction was rolled back
twice when Lua procedure was invoked from CALL.

Change the way arguments to and from CALL
statement in the binary protocol are passed:
we used to pass everything from the wire as a single
binary blob. Now every field of the received
tuple is passed in as a separate string argument.

Everything passed back from Lua is converted to a tuple. This
makes CALL response similar to one of SELECT.

Improve box.pack() to convert its argument to integer when
necessary. Add an argument count check to box.pack().
Additionally, now box.pack() can be used to pack
operations of 'UPDATE'.

Use tarantool_lua_tostring() in iov_add_ret():
this function is now used to convert return values to
the binary protocol in box_lua.m. This is necessary
if we try to send boolean or nil over the
binary wire, since Lua C API lua_tostring()
does not convert them.

Add box.lua - a system Lua script
compiled into Tarantool and containing a bunch
of Lua code preloaded at startup.

Populate box.lua with implementation
of basic Lua functions:
box.select(), box.update(), box.replace(),
box.insert() (currently an alias for box.replace()),
box.delete(). They are all wrappers around box.process().

Move box_lua_init() to the beginning of mod_init(),
since Lua in future can be used in recover().

Fix a wrong assumption about the contents
of Lua stack in iov_add_multret().

Update sql.g Python SQL grammar to allow
an empty argumeent list for procedure in CALL
statement.

Add initial documentation on Lua procedures.

Add more Lua tests.

Unrelated: rename INSERT to REPLACE, and UPDATE_FIELDS to
UPDATE.
Remove SELECT_LIMIT, which is not used any more.

This allows to immediately call from modules stored
procedures defined in the administrative console.

Instead of using "print" and fiber->iov
to return results to the client, change the Lua procedures
implementation to simply send to the client all return values
of a procedure. A procedure, in turn, can return tuples, integers
(and, in future, strings, Lua tables or whatever).

This allows nicely to call one procedure from another, and use its
results in Lua, and call the very same procedure from the binary
protocol, and still be able to process its results on the client.

Remove dead code from txn_cleanup(), which
would check that txn_cleanup() is not called twice:
this code is from the time when we used

Rename txn_abort() to txn_rollback().
Rename txn_alloc() to txn_begin().

Introduce box_out interface, used to
send box results to the client. Lua uses
this interface to intercept returned tuples
and push as return values to Lua stack.

Make iov_add/iov_dup inline, as they used
to be. They are now mostly used from within
callbacks.

Make txn_commit()/txn_rollback() non-static
as they are now used in memcached.m.

Introduce memcached_get(): implementation
of Memcached GET statement. Wrap memcached_get()
in proper txn_begin()/txn_commit()/txn_rollback(),
and handle failure of memcached_get() by
rolling back the transaction.
Split BOX_QUIET to two flags: BOX_GC_TXN and
BOX_QUIET.
BOX_QUIET had a side-effect that txn_cleanup()
was done immediately, rather than by fiber_gc().
This had the side effect that txn_commit() could
not be used in memcached_get(), because in
memcached_get() we need both BOX_QUIET and txn_cleanup()
called from fiber_gc().

Now that we have box_out interface, eliminate
BOX_QUIET flag completely, and use box_out_quiet
set of callbacks instead.

Fix a bug when Tarantool exceptions were intercepted
by Lua in lua_pcall(), and converted to Lua errors.
Let Tarantool exceptions pass freely through Lua, by using
lua_call() instead of lua_pcall().

In case of any Lua error lua_call() aborts execution of the
entire process. Register lua_atpanic that converts
lua errors to Tarantool exception ER_PROC_LUA.

Unwinding the stack in this manner didn't work properly
with libcoro 6.0, which we were using. Update
libcoro library to version 6.06 to fix this problem.

Complete the renamve of all iov functions.

Spell check the comments.
Remove unnecessary changes. Be strict about
not including more than necessary.
Update copyright headers.
Do not put static functions after non-static:
a function can become non-static in future,
and it should not require moving it around in
the .m file.

Rename all iov_ functions to use a common prefix.
This is used in the patch which adds hides box output
behind an interface, and allows results of
box.process() to be returned directly into Lua.

Fix a memory leak when remote address was allocated
in etet_pool (eternal memory pool) in recovery_follow_remote
(start of replication).

Remove fiber->data, as redundant and confusing.
fiber->f_data is sufficient for all possible needs.

Fix a bug when fiber_server::data was never initialized
but passed to "on_bind" callback of fiber_server
(this worked since no single "on_bind" callback uses
its "data" argument).

Conflicts:
	cfg/tarantool_box_cfg.c
	cfg/tarantool_feeder_cfg.c
	cfg/tarantool_feeder_cfg.h
	test/CMakeLists.txt

Function tnt_io_sendvu was moved to tnt_io_sendv_direct. Compile flags was
added. Warning was clean-uppend.

Function tnt_io_sendvu was renamed to tnt_io_sendv_direct
Check IOV_MAX routine in tnt_io_sendv_direct was added.

* size's update

* size/count types update

Conflicts:
	connector/c/tnt_io.c

tnt_io_connect_do routine was updated.

* connection tmout signals handling

* tnt_set_allocator()
* tnt_tuplef()

Function was moved to tuple implementation. Funcnion valid_tuple was
renamed to tuple_length.

The box tuple implementation was moved to separate file. Tuple flags
NEW and SEARCH was removed (unused). box_mode enum was removed (unused).

libdl was added.

CALL accepts flags and a tuple (list of fields).

Add CALL support to the sql.g parser (Python
testing environment).

Add two new error codes: ER_PROC_LUA (an
error inside Lua procedure) and ER_NO_SUCH_PROC.

Since so far there is no way to create a stored
procedure (one needs to rebuild Tarantool to pre-load it),
this addition has little practical use.

Add tuple print-out in yaml format, to be able to
print Lua procedures output in the administrative console.

Add box.process() function, the main callback into
box from Lua. It takes a binary packet and passes it
on to box for execution. The results of execution
are added to fiber iov vector, so we can always
just grab them and print out, which we do in the
administrative console.

Implement rudimentary Lua support in the administrative console.
Remove exec module command, it's not used and we now
have Lua for similar purposes.

Add a first Lua module, "box", which
has only one function -- "pack", and test it.
'pack' is derived from box.tbuf module in the
original Lua patch.

Fix a bug in box-protocol.txt, tuple format
description.

Add a copyright header to include/errcode.h (unrelated).

Implement a prototype for Lua initialization
procedure: there is a function tarantool_lua_init(),
which any code, core or modules, can call.
tarantool_lua_init() calls mod_lua_init() to
add module-specific Lua extentions.

Fix a bug in mod/CMakeLists.txt, generate_admin_c
CMake target didn't exist, so admin.m wasn't
re-generated correctly when admin.rl was changed.

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.