Adding new fields Last_{IO,SQL}_Errno and Last_{IO,SQL}_Error to output
of SHOW SLAVE STATUS to hold errors from I/O and SQL thread respectively.
Old fields Last_Error and Last_Errno are aliases for Last_SQL_Error and
Last_SQL_Errno respectively.
Fields are added last to output of SHOW SLAVE STATUS to allow old applications
to use the same positional arguments into the row, while allowing new
application to benefit from the added information.
In addition, some new error codes are added (especially for the I/O
thread) to be able to provide sensible error message.
rows event):
Adding a after image COLS bitmap to Update_rows_log_event (for telling
what columns that are present in the after image of each row update).
Also fixing case where Rows_log_event length was not correctly computed
(happened when the number of columns in a table was more than 251).
does not work): Changing packed row format to only include null bits
for those columns that are present in the row as well as writing BIT
columns in a storage engine-independent format.
The change in row format is incompatible with the previous format and a
slave will not be able to read the new events.
