Add a way to do nested iteration in Lua stored procedures.
Implement destruction for tree indexes and iterators.
This clears a few valgrind warnings.

Fix connector_c test.

Finish porting index API to objective C.
Change all methods to become objective C methods.
Implement a family of virtual constructors and destructors.
Change iterator allocation scheme.

Use the index iterator API in memcached.m,
instead of hard-coded access to index internals,
which broke index abstraction.

This (temporarily) can (somewhat) break expire
in presense of SELECT command against memcached namespace,
since SELECT uses the same iterator.

Hopefully, it's only temporary, since we'll soon
be able to have more than one independent generic iterator
over the same index.

Do not pre-allocate Index object.

Fix valgrind errors.

A pre-requisite patch for turning Index into an Object:

Extract key description into an own structure, struct key.

Introduce key_config function, which
transfers configuration from confetti structure
into struct key.

This allows to decouple index construction from
key construction -- something you need
if you want a virtual constructor for index.

SHOW INFO now prints path to config
Review Dmitry's patch, fix tests.

Port first two patches of branch index-2objc.

We decided to use objects for indexes to ease addition
of more specialized index types (such as primary key tree
indexes, spatial indexes).

Work done by Konstantin Shulgin.

Incorporates review fixes. This patch:

 - makes struct index an Objective C class,
 - adds init and free methods,
 - moves allocation of sp_tree struction to heap (used
 to be allocated in the pool allocator) since we may
 in future create/drop indexes on the fly,
 - updates method calling signatures.

paramaters use floating point representation.

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.

Implement box.tuple.unpack(), which converts the tuple
to a list of lua atoms.

Add fiber.cancel(), fiber.sleep(), fiber.testcancel(),
fiber.id().
Draft the fiber library interface description.

Add tuple::pairs() and tuple:next() implementation.

Update tuple metatable __index implementation to do
method lookup.

Fix a bug in box.unpack() where we wouldn't check that
lua_tolstring() can return NULL (which happens if nil
is on the stack).

Add tests.

Implement iterators, range select, namespace truncate.

Simplify index_tree_el_compare
Make iterators usable regardless of index type.
Add coverage.

Add more tests.

In iterators over tree indexes, check
that key type matches field type.
Add tests for non-unique multipart keys.

Update output of the python test library
to not print extra trailing '\0' at the
end of error message. Update test results.

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.

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.

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.

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.