* Removed all functions and extensions that treat utf16 input
* Now only UTF-8 supported

Closes #2295

Straightforward change to remove redundant `sql-` prefix
from tests in `sql` test suite.

Update for the hackish usage of space_def, update for
_trigger system space

Review fixes.
Part of #2435.

* better messages
* fold sql_prepare()
* rewrite the message decode

Add iproto_execute command to get not only sql rows as the result,
but also sql meta data about each result column.

Make SQLITE_LIMIT_VARIABLE_NUMBER be static

SQLITE_LIMIT_VARIABLE_NUMBER is the run time limit of the
variable count in the query. The Tarantool doesn't support dynamic
limits for such things. Let's make this limit be enum instead
of value in the limits array (struct sqlite3.aLimit).

Part of #2285.

dh_systemd_enable called BEFORE dh_install, which installs file(s)
(tarantool.service), required for dh_systemd_enable. A quick workaround
is to symlink tarantool.service into debian/ directory.

Issue appeared only in cdbs comming with Debian 9.

See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=864489

Thanks for Alexander Sbitnev

+ Fix inconsistent debian/changelog and debian/control.

Needed for #1906

So that vy_tx does not depend on vy_cursor.

Needed for #1906

Needed for #1906

We can't move vy_index_new() to a separate file right now, because it
depends on vy_env and we can't just replace vy_env with vy_index_env and
vy_cache_env there, because the function is called from outside vinyl.c.
To deal with that, let's introduce wrappers around vy_index_new() and
vy_index_delete(), vy_new_index() and vy_delete_index(), which are vinyl
C API functions that simply call the internal functions with appropriate
arguments. Also, remove vy_index_ref() and vy_index_unref() from the C
API, as they are not really necessary.

Needed for #1906

 - Introduce vy_index_env hosting fields common to all indexes and
   replace vy_index->env with it.
 - Use a callback to trigger async upsert squashing.
 - Pass vy_env or vy_schedule in function arguments instead of using
   index->env.

Needed for #1906

So that we can remove vy_env reference from internal Vinyl structures.

Needed for #1906

Needed for #944

alter: remove snprintf from func_def_new_from_tuple

Now vinyl's rollback to TX savepoint doesn't work in case when one
TX has several statements modifying the same key.

A simple example is presented in gh ticket 2589.

Fix it.

Add a big test that compares vinyl with memtx in case of many
failing (catched with pcall) statements done in a transaction.

Fixes #2589

Add `sqlite3BitvecBuiltinTest` to exported symbols to expose
it to ffi. Bug #2590 submitted to remove it from exports.

Now if a TX (in vinyl) changes the same key again, it uses
previously created struct txv and updates the tuple in it.
Therefore the change is not added to the transaction log; instead,
the old entry in the log is updated.

At the same time, the order of TX log is important, especially when
there are several indexes in a vinyl space: tx_prepare traverses
TX log, determines the beginning of a tarantool statement (that
could consist of several vinyl statements) and behave with several
conjuncted txvs as a whole.

Fix it by leaving old txv and always creating new txv.

Fixes #2577

- don't reference the upserted tuple twice in vy_tx_set(..)
- handle txv allocaion error properly in vy_tx_et(..)

The return value of txv_new was not checked.

Raise syntax error in a case of empty requests. Update sql-tokenizer
to support exising tests.

Test alias.test.lua is fully disabled, see #2582

Part of #2381

Instead introduce vy_run_env_enable_coio(), which starts reader threads,
and make vy_run_iterator automatically switch to coio if reader threads
are running. With this patch, vy_read_iterator doesn't need a pointer to
vy_env to add a run as a source, only vy_run_env.

While we are at it, cleanup vy_conf a bit.

Needed for #1906

vy_run_write_page() doesn't take a reference to last_stmt, because it
assumes that the write iterator guarantees it won't be deleted until
'next' is called again. The iterator does pin a statement if it is read
from a run file - see vy_write_iterator_set_tuple() - however there's a
case when the last returned statement can go away under us. This will
happen if the iterator is used for major compaction and the last source
statement is a DELETE. In this case the iterator will unreference the
last statement it returned to the caller, take a reference to the DELETE
instead, but won't return the DELETE - see vy_write_iterator_next(). As
a result, the caller, i.e. vy_run_write_page(), will hit use-after-free
on an attempt to read last_stmt.

To fix this bug, let's make vy_run_write_page() take a reference to
last_stmt as it used to before the write iterator was reworked. A test
case will be added later, after all iterator-related issues have been
fixed.

Closes #2578

Iconv is a library to convert a sequence of characters in one
character encoding to a sequence of characters in another character
encoding. Example below converts utf-16 big endian string into utf-8
string:

    convertor = require('iconv').new('UTF-16BE', 'UTF-8')
    converted_string = convertor(source_string)

Closes #2587

vy_task_dump_new() deletes empty in-memory trees right away, but
doesn't increment vy_index->mem_list_version, which may result in
a read iterator crash accessing a deleted vy_mem.

Now open MP sort is used for any size of an array.
For small arrays it's an overkill and even can cause overhead
due to thread pool creation.

Invoke open MP sort only for big arrays and use old good
single-thread qsort for small arrays.

Fix #2431

Print original uri as is if it doesn't contain sensitive
information.

Closes #2292

Currently, quota (and some global stats) are adjusted in
vy_index_commit_upsert(), vy_tx_prepare(), and vy_tx_commit(),
which entails dependency of vy_index and tx_manager on vy_env.
Let's move this code to the upper level, i.e. to vy_prepare()
and vy_commit().

Needed for #1906

Remove box.info.vinyl().performance.{tx_rlb,tx_conflict}. Instead add
'tx' section to box.info.vinyl() with the following counters:

 - 'active': number of active transactions
 - 'commit': number of committed transactions
 - 'rollback': number of rolled back transactions
 - 'conflict': number of transactions aborted on conflict

Apart from improving vinyl statistics, this patch also pursues one more
goal: removing dependency of vy_tx and tx_manager on vy_env, which is
needed to move them to a separate source file.

Needed for #1662 #1906

It belongs there, really.

Currently, during local recovery, an index is added to the
scheduler from vy_index_recover(), which makes this function
depend on index->env->scheduler. Let's postpone addition to
vy_index_commit_create() as we do when vinyl is online.

Needed for #1906

Needed to remove dependency of vy_index on struct txv.

Needed for #1906

Before this patch, the new space, created by alter specification,
would be put into space cache only after successful WAL write.

This behaviour is not linearizable: on a replica, the WAL is
played sequentially, and the order of events could differ from the
master.

Besides, it could crash, as demonstrated in gh-2074 test case.

Since we use a cascading rollback for all transactions on WAL
write error, it's OK to put a space into space cache
before WAL write, so that the new transactions apply to the new
space.

This patch does exactly that.

All subsequent requests are executed against the new space.

This patch also removes on_replace trigger in the old space, since
all checks against the new tuple format are performed using the new
space.

Fixes #2074.

* UTF-16 support removed
* Tests with UTF-16* cases removed

Closes #2295