Adding Tarantool connector for YCSB

In "mail.ru" we wrote and widely use Tarantool/Box key-value database. It's key properties include:
1)all data is maintained in RAM
2)data persistence is implemented using a Write Ahead Log and snapshotting
3)supports asynchronous replication and hot standby
4)uses coroutines and asynchronous I/O to implement high-performance lock-free access to data
5)available on Linux, FreeBSD, Mac OS X
6)stored procedures in Lua provide high level of customization. In particular, the message queuing API is a set of stored procedures running on top of the basic functions to store, modify and retrieve tuples.