In this commit we are adding three more status variable to SHOW SLAVE
STATUS.  Slave_DDL_Events and Slave_Non_Transactional_Events.

Slave_DDL_Groups:- This status variable counts the occurrence of DDL
statements

Slave_Non_Transactional_Groups:- This variable count the occurrence
of non-transnational event group.

Slave_Transactional_Groups:- This variable count the occurrence
of transnational event group.

Patch Credit:- Kristian Nielsen