Since tarantool can use different allocators, we need a single
interface for getting statistics that is suitable for all allocators.
Follow-up #5419

Firstly, Allocator::stats() must accept callback function and its
argument to fulfill small interfaces.
Secondly, unify stats and store both system and small allocators
statistics in the same structure in order to use ::stats() method in
foreach_allocator() helper.

Follow-up #5419

Let's initialize them in the dedicated allocator.cc source file

Follow-up #5419

Wrap the exported readline function to avoid clash of symbols.

Part of #5932

For the same reason why 'uri' was moved to src/lib - SWIM needs
core and uuid, and SWIM will live in src/lib.

This commit follows 'uri' relocation as a separate one because
'uri' relocation required some changes in the files, moved by
this commit.

Needed for #3234

Basic port structure does not depend on anything but
standard types. It just gives an interface and calls
virtual functions.

Its location in box/ was ok since it was not used
anywhere in src/. But next commits will add a new
method to mpstream so as to dump port. Mpstream is
implemented in src/, so lets move port over here.

Needed for #3505

Reorganize iproto parser (pickle) around two pointers at the request
parsing position and request end.
This makes the code more generic and easily usable in lua and
with new buffered I/O.

This also reduces the current widespread use of tbuf throughout
entire code base (good for future maintainability of the code).

End the copyright madness. Tarantool authors maintain a shared
copyright on the code base. Remove individual copyright (c) from
specific files and put a single AUTHORS file in the project top.

An intermediate step, use size0 for 'size' temporarily,
to ensure there are no compilation errors.

This is a code review of Konstantin Shulgin's branch
refactoring-tbuf.

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.

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

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.

Send error messages to the client.

Before this patch, Tarantool would only send an error
code to the client, but record all the details in its error log.

This patch extends the client/server protocol and adds
error text to it. This text can now contain not only
a staple message that corresponds to the error, but
problem-related additional information, such as namespace id,
field number, etc.

All errors still can be logged in the error log, but
not all of them need to be. For errors, which are only
sent to the client, this patch uses ClientError exception
class. Errors which also need to be logged in the error log
must use LoggedError exception class.

To choose between the two, the following rule of thumb is applied:
- client application errors, which, generally, can be non-errors at all,
  such as access to a non-existing namespace, index or field, or
  access to a locked tuple are not logged
- execution and protocol errors, such as an error writing to disk,
an message that doesn't follow the protocol format, is logged.

For the most common error, ER_TUPLE_IS_RO, we do not use
string template to reduce CPU cycles necessary to produce this error
(on my machine one can raise ~200 000 exceptions per second, which is not
too much).

An addition to the above, this patch renames error codes, to
make them shorter (ERR_CODE_* -> ER_*) and rewrites the iproto.m
client connection loop to make it a trifle more efficient.

This patch also fixes a couple of bugs:
- in exception.m, [tnt_Exception alloc]
when we reused the old exception class, we did
not reset its 'isa' pointer, which could lead to a crash
when a message with a different signature was sent to
it.

- in box_dispatch (renamed from box_dispach),
when logging for slow commands was done, txn->op could
already be overwritten by txn_commit()/txn_abort().

A comment on the naming scheme: prefixing every Tarantool
piece of method/data structure with tnt_ would lead
to very bloated code. So in this patch
I decided to reduce the use this
prefix to the client library code and some very
generic names only.

Replace all custom raise macros with general tnt_raise one.

mod/box:

Remove in_recover and write_to_wal fields from txn and use
 BOX_QUIET and BOX_NOT_STORE flags instead.
Move verification of allowed commands from txn_begin to
 box_process_rw/box_process_ro functions.

Port tarantool to ObjectiveC.
Implement basic TNTException class and
 TNTFiberException and TNTBoxException subclasses.
Replace longjmp/setjmp with ObjectiveC exceptions.

mod/box: Restructurize request processing in the following way:

	try
		begin
		dispatch
		commit
	catch
		abort

where any error during request processing generate an exception.

Implement
https://blueprints.launchpad.net/tarantool/+spec/consistent-header-guards

Audit all header files in tarantool code base for consistent use
of header guards:
- consistent naming scheme, following doc/coding-style.txt
- header guard goes before the copyright
- each header is self-sufficient.
- add copyright headers where they were missing.

Remove __packed__, __unused__, __noinline__ and __regparm2__ from util.h,
since the name __unused__ conflicted with a parameter name in
third_party/valgrind/valrgind.h, which led to a dependency in inclusion
order between util.h and this header. The define names were not standard, I
couldn't come up with some meaningful and standard names, and they were only
saving some typing, while not providing any extra functionality.

Implement a basic SQL parser.

Implement SQL statements: INSERT, UPDATE, DELETE,
PING.

Add a test case that tests INSERT/SELECT/DELETE.

Other changes:

Remove support for result-prefix from admin.py
Rename admin.py to tarantool (tarantool client).
Add readline support to tarantool client.
Make sql.g and sql.py independent from yapps
Add gdb support to ./test-run
Disable all optimizations when compiling with DEBUG.
Fix a few bugs discovered by trial and error in silverbox
protocol description.
Add automatic reconnection in case of server disconnect
to test connections. This is used to automatically
reconnect to the server after server restart or reinstall.
Implement soft and hard (with and without removal of vardir)
server restart.
Make show.test results independent from other tests (data I/O
skews statistics, and there is no way to reset it without
restarting the server).
Add  TCP_NODELAY to fiber sockets.