Annotate rows events

Laurynas: upstream 5.6 implemented binlog_rows_query_log_events, https://dev.mysql.com/doc/refman/5.6/en/replication-options-binary-log.html#sysvar_binlog_rows_query_log_events, closing

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 Annotate rows log events
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Store in binlog (and show in mysqlbinlog output) texts of statements that caused RBR events.
This is needed for (list from Monty):
  * Easier to understand why updates happened
  * Would make it easier to find out where in application things went wrong (as you can search for exact strings)
  * Allow one to filter things based on comments in the statement.

The cost of this can be that the binlog will be approximately 2x in size (especially insert of big blob's would be a bit painful), so this should be an optional feature.
Varible :variable:`skip-annotate-rows-events` of **mysqlbinlog** utility allows to do not print *Annotate Rows Events*.
Variable :variable:`binlog-annotate-rows-events` of **mysqld** tells the master to annotate RBR events with the statement that caused these events.
Variable :variable:`replicate-annotate-rows-events` of **mysqld** tells the slave to write annotate rows events recieved from the master to its own binary log. Sensible only in pair with log-slave-updates option..