Fix bug https://bugs.launchpad.net/tarantool/+bug/837315

When write_inbox() failed, wal_write() would throw
an exception.

This had two effects:
first, a call to confirm_lsn() would confirm lsn
of the failed transaction out of order (indeed, nothing
is written, so this lsn is confirmed before lsns
of transactions which are waiting on write to complete)

second, txn_rollback() was called with fiber->mod_data.txn == 0.

The second led to an assertion failure.

The fix only fixes the second effect, so that an error
is sent to the client, and the server does not terminate.

It's not possible to come up with a serial test
case for the bug, since to fill up all inboxes one
needs many concurrent writes.

Remove the restriction on type of primary key index.

Fix a compilation error.

Implement iterator over HASH index, and use it
in mod_snapshot() and build_indexes().

Change signature of index_tree_el_init, avoid
unnecessary use of palloc(), preallocate
buffers for reads and writes instead.

Reorganize loops in build_indexes() to avoid redundancy.

Rearrange code in build_indexes() to avoid
extra loops.

Split build_indexes() into two functions,
to avoid 4 levels of nesting.

No functional changes.

Eliminate server start/stop/deploy cycle for blueprint
'tree-primary-key' tests. Move the tests to box_big suite.

Add coverage.

Rename tree_index_member to index_tree_el. Realign code to fit 80
columns.

The patch doesn't change code in any way, only performs a rename.

Remove an unused box_hook_t declaration.

Use method name that don't make me bite my tongue
when reading the code.

Use subject-verb-object scheme prevalent in most languages.

When subject is a compound, use class-order-family-genus-specie
to identify it fully.

A fix for Bug#850031 "Assertion failure in iproto_interact()".

Fix fiber_bread() to read at_least bytes, not
buf->len - at_least bytes, as it used to work before.
Many places that call fiber_bread rely on this.

Print userdata for index in a non-suggestive, but
informative way.

https://blueprints.launchpad.net/tarantool/+spec/tree-primary-key:
Allow "TREE" index type for primary key: code review.

Conflicts:
	mod/box/box.m
	mod/box/index.m

Allow to invoke insert/update/delete/select/replace
directly on box.space objects.

Add box.space[i]:len(), which returns the
number of tuples in the space.

Add rudimentary index object support.

Add tests.

Implement INSERT command in Box. Minor cleanups in Lua.

https://blueprints.launchpad.net/tarantool/+spec/namespace-to-space

Rename 'namespace' to 'space' everywhere:
in configuration, in implementation, in documentation.

Add access to space configuration to Lua.
Make configuration in Lua read-only.

Provide access to server configuration in Lua.

https://bugs.launchpad.net/tarantool/+bug/730613

Document Bug#730613, "SELECT with a disjunction
on multiple keys returns matching tuples twice".

Now that confetti supports it, use boolean for true/false
yes/no config options.
Update the manual accordingly.

test environment:
  - luajit suppressions was added.

Install a filter to not include a local path into
a test results.

Fix the code which allocates Lua coroutines to properly
destroy them: the old code could destroy the same coroutine
twice, or never at all.

Remove auto-generation of tarantool_box_cfg.cfg.
This was intended as a sample configuration
file, but it is no longer syntactically correct,
and thus can not be used.
Besides, there are now semantical rules on top
of the syntax restrictions (e.g. you can't define
memcached_expire on a replica), which also
make the auto-generated config incorrect.

Remove it to not mislead first-time users into
trying it out.