In the newest 1.7 the call/auth/dml_request decode the data
directly from a struct xrow_header instead of MessagePack data.
Make the same for sql_request.

obuf_alloc can not be used as a temporary buffer per sql row column,
because each column can be allocated in different slabs. It makes
impossible to allocate a port tuple from several intervals:
[col1_begin, col1_end], [col2_begin, col2_end], ...

Region has region_join method, which can realloc memory blocks from
different slabs in monolite memory area - [begin, end].
It allows to use tuple_alloc for port tuples.

Closes #2602

Closes #2601

The original SQLite doesn't account DDL changes at all. Such changes
simply do not update the sqlite3_changes() return value. But iproto
clients want to know a result of DDL operation, particularly for
IF [NOT] EXISTS DDL operations.

We cannot return real count of affected tuples, because it depends on
the tarantool version. For example, now DROP TABLE deletes tuples from
_space, _index, _truncate and _trigger. But in the future this set of
system spaces can be changed.

With considering the above remark, lets return always for all DDL
operations either 0, if nothing happened, or 1, if something was
created, deleted or modified.

Closes #2617

Reformatted according to Tarantool's coding style.

Part of #2628

* test/unit/sql-bitvec.test.c - rename to test/unit/sql-bitvec.c
* sql-bitvec.c - update from gh-2590-bitvec-test-convert
* sql-bitvec.result - update from gh-2590-bitvec-test-convert

Closes #2590

Introduce dedicated opcode OP_TTRansaction, which is
responsible for initiation of Tarantool transaction.
This opcode is only emitted if statement is generated
directly by parser. That means that changes like insertions
into system tables are not covered by Tarantool's transations.

Tarantool's transaction is committed or rolled back during
exectuin of `Halt` opcode. `CloseAllCursors` function was
splitted into two: in order Tarantool's WAL to work need to
preserve allocated memory until commit to WAL. Call this
deallocation after Tarantool's commit.
In future this will be re-worked since transaction can be
either in statement or generic, and not all Halts should commit.

Also, fix a bug: memory area passed to WAL were re-used. WAL itself
doesn't do memcpy, so this state of affairs was lead to unpredictable
errors during save/restore. Use region_alloc to reserve memory area
for WAL in tarantoolSqlite3Insert and tarantoolSqlite3Delete.

Closes #2599

Now write iterator see only oldest vlsn. Because of it
the write iterator can not skip or merge or squash
newer statements, even if they are not used by any
transactions. For example, consider one key and its lsns:

      LSNs:  10   20   30   40   50
Read Views:  *         *         *

Statements with lsn 40 can be merged with 50;
20 can be merged with 30.
Old write iterator will merge nothing in that case,
because there is oldest vlsn = 10.

Lets allow the write iterator to see all read views, instead
of only oldest.
Such write iterator can merge multiple lsns subsequences
of each key.
For the example above it will merge in the following way:

      LSNs:   10   20   30   40   50
Read Views:   *         *         *
  Merge and  \__/\_________/\________/
    return:    merge,   merge,   merge
             and return each merged result.

For the considered case the difference is 3 result statements
instead of 5 by the old write iterator.

Closes #1920
Closes #2502
Closes #1824
Closes #2578

Follow up #2507, needed fir unit tests

Closes #2507

Part of #2507

Closes #2543

Disable background and usermode when NOTIFY_SOCKET is set.

Closes #2538

Admin console should be started before the box.cfg() call.

Closes #2079

Now module.h is autogenerated automatically on `make all`
if one or more source header files have changed.

Closes #2481

Check that vinyl can recover if vinyl_memory is lowered after restart.
In this case it should forcefully use quota and schedule dump after
recovery is complete.

Needed for #2397

Check that:

 - Empty spaces are recovered correctly.
 - Data is restored fully, for every index.
 - In-memory data is not lost.

Needed for #2397

 - Make vinyl/split_coalesce restart the server and check the space
   content after splitting and coalescing ranges.
 - Do not split ranges in vinyl/recover test, as it is now tested by
   vinyl/split_coalesce test.

Needed for #2397

vinyl/coalesce already tests range splitting, no need in
a separate test case.

Needed for #2397

On space alter (index create/drop) new_space->truncate_count is left
unset, which breaks vinyl recovery logic: in vinyl we assume that if
index->truncate_count (restored from vylog) > space->truncate_count,
the space will be truncated and so there's no need in applying a WAL
row (see vy_is_committed_one()). So if an index is dropped or created
after truncate, vinyl won't apply statements for it on recovery.

Closes #2615

An index can be dropped and then recreated with the same space/index id.
To discriminate between different incarnations of the same index during
recovery, we use index LSN stored in index options, as it is supposed to
be unique. However, the uniqueness property doesn't always hold:

 - If two indexes are created from different fibers, they might receive
   the same LSN.

 - If an index is created by inserting a record into _index system space
   directly, without using the public API, as it is the case in case of
   logical backup, its LSN might conflict with the LSN of an existing
   index or a previous incarnation of the same index stored in vylog.

These exceptions can result in unrecoverable errors during local
recovery, like this one:

  F> can't initialize storage: Invalid VYLOG file: Duplicate index id 3

Besides, storing LSN in index options is ugly, because LSN isn't a
user-defined option - it's a part of the implementation.

To fix this issues, let's use the LSN passed to Index::commitCreate,
i.e. the actual LSN received by the row that created the index. There's
one problem though: snapshot rows don't store LSNs. However, it doesn't
mean we can't find the index in vylog corresponding to a snapshot row:
we just need to look up the index by space_id/index_id instead of LSN
and then compare the snapshot LSN with the LSN of the last index
incarnation stored in vylog - if the latter turns out to be less, then
we need to load the index, otherwise the index is going to be dropped
and we need to load a dummy index. For more details, see the comment to
vy_recovery_load_index().

Another issue that needs a clarification is backward compatibility. The
thing is the LSN written to the index options lags behind the actual LSN
assigned to the row that created the index by 1. So to preserve backward
compatibility, we use LSN from index options for legacy indexes that
have it, while for indexes created after this patch we don't store LSN
in index options (set it to 0), neither do we use it on recovery (use
row LSN instead).

Closes #2536

Currently, 0 is passed to Index::commitCreate as index LSN during
initial join. To stop using index_opts->lsn for identifying indexes in
Vinyl, we need a unique LSN. So let's install a dummy journal to assign
fake unique LSNs for rows received on initial join.

Needed for #2536

So that we could use it instead of index_opts::lsn.

On initial recovery pass the snapshot LSN instead as we don't store LSNs
in memtx snapshot.

Needed for #2536

Reload schema after DDL SQL operations.

Closes #2569

Implement tuple_arena_create method to initialize tuple arena and
quota. This method further will be used to initialize both
memtx and vinyl arenas.

Write a test showing the limit of vinyl statements size.

Part of #2569

Now if an error happens during the first tuple push from port to
obuf, the port is not actually destroyed - only the first tuple is
unreferenced.

I believe that port dump must not free any data at all, then once
a user creates a port he must take the ownership and destroy it in
the end of usage. That would simplify the user code, especially C++.

Simplify port_dump function and destroy a port in the code that
creates the port.

LuaRocks requires openssl and curl in order to download
manifest from rocks.tarantool.org.

Fixes #2612

Fix compatibility with original tarantool/http client.

Follow up #2530

Closes #2608