* implement two new calls:
  box.error.last() - returns last error, if any, as a Lua table
  box.error.clear() - clears the last error

* add an alias for box.error(), box.error.raise()

 - mysql moved to https://github.com/tarantool/mysql
 - pg moved to https://github.com/tarantool/pg

Please consult documentation on GitHub for more details.

Encapsulate trigger management, as well as undo managemnt
specific to memtx in the engine. Fix a potential memory leak
in MemtxEngine::rollbackStatement(), with wrong reference counting
for rolled back tuple.

Always generate redo record, even in wal_off=true mode, this
simplifies txn_commit().

*) fixed several comments and minor bugs
*) after CR fixes

Update comments, rename matras_extents_count() to matras_extent_count().

Provide access to iproto sync via session.sync() binding.

The value is valid only at start of a Lua call before the first yield,
after which it may be replaced with a sync from another request
running on the same session.

+ Check Lua types for uint/decode for msgpack(ffi)/json/yaml tests

Include all neede variables to tarantool.h

tarantool.h is an external header (perhaps), so not available with
plain #include ""

Conflicts:
	CMakeLists.txt

Tell matras table that you're about to change a location
before actually changing it.