Prototype for Pg driver
Merge branch 'master' of github.com:mailru/tarantool into sql
Postgresql driver is ready (at first step)
MySQL driver pre-alpha
Merge branch 'master' of github.com:mailru/tarantool into sql

Conflicts:
	CMakeLists.txt
	src/CMakeLists.txt
	third_party/luajit
Migrate to C++, too
Return back luajit submodule
Migration to C++ was done.
Postgresql and MySQL drivers are ready.
Tests depend on MYSQL and PG environment variable.
:quote methods for Pg
SQL connectors provide transaction.
Merge branch 'master' of github.com:mailru/tarantool into sql

Conflicts:
	include/guard.h
Drop alloca from exception. Throw only by static strings.
Copy error string to lua buffer before exception.
Extract mysql and postgresql drivers to plugins.
Delete double underscore, fix uncertainty in test.
Merge branch 'sql'