Rename tarantool_pthread.h to tt_pthread.h

This is a pre-requisite for addition of Perl stored procedures.

Don't load corrupted tuples.

Reference commit  4bc5e917c8cd5fc2f6b217512ef530007529322f
(2.1.0 tag, stable).

Preserve the zero-warnings patch.

Inline bio_socket_close().
Don't allow connect/bind on a non-empty socket:this is error-prone.
Don't allow connect/bind on a socket which
is already connected/bound/used for something else.
This is error-prone.
Move bind_addrinfo to evio layer.
Don't create iobuf without need. In close(), set iobuf to NULL.
Timeouts are not exceptions. Merge _timeout and other calls in coio.

Move third_party library compilation to the top level (less
directory traversal).
Provide an option for using system LibEIO/libobjc.

Enforce a naming convention for cmake/ scripts
(Find* and Build*).

Move ev and eio wrappers to third-party (todo: delete
them completely).

There is one (known) problem with this patch:
tarantool --version now prints incorrect compile flags.
To be fixed in a separate patch.

A fix and a test case for Bug#1051006
"Tree iterators return garbage if an index is modified between calls"

Mark in a deleted node in sptree.h that it's been  put into the
garbage heap. When iterting over a garbage collected node, skip it,
and go up the stack until we find the first valid node.

This breaks the "sorted" quality of tree iterators in case there
are modifications between invocations of an iterator:
it is possible that a node is deleted and recycled, and we don't see
it in the iterator. When we go up the stack, we can jump to a different
part of the range than the one the recycled node belongs to.
. With this fix, it is also possible, that the iteration goes more
than once over entire tree range. But it's a good enough quick fix for a
crashing expire loop, which uses the tree iterator over the primary key to
scan the entire range and deletes expired keys on the go (additionally,
deletions may occur between invocations of the expire loop).

Fix a regression with nested @finally not being
called, introduced in 1.4.7 release.

Big thanks to David Chisnall for a swift fix in GNUStep Objective C
runtime.

Add unit tests for two Objective C runtime properties:
nested finally handling and ability to catch C++ exceptions.

Do not use bundled libobjc on Darwin.
Refactor cmake scritps: introduce os.cmake, arch.cmake,
compiler.cmake, libobjc.cmake, luajit.cmake.

Remove the hack with building libobjc/luajit as a
dependency on cfg.

Do not specify -ggdb when compiling with clang.

Add -fno-objc-legacy-dispatch and -fobjc-nonfragile-abi
when compiling with CLang on Linux.

Remove -fgnu-runtime when compiling with gcc on Mac.

Many minor cleanups.

Add a makefile to libobjc.

See README in this patch for a description of the import
procedure.

Darwin revealed a bug in our free_proc_title() function, which was
added to procitle.c to work well with valgrind: we free argv pointer
even if it wasn't allocated (none of PS_USE_CLOBBER_ARGV/PS_USE_CHANGE_ARGV
was set).

Don't free memory if it wasn't allocated.

Another issue is understanding why Darwin doesn't define
PS_USE_SETPROCTITLE and why our FreeBSD port didn't hit this bug.

Extend queue.h with STAILQ_SPLICE and STAILQ_REVERSE.
Test the new functions in a simple unit testing framework.