Makeing rpl_filter for each Master_info.

Users can set different repplication filter rules for each replication connection, in my.cnf or command line.
But the rules set online will not record in master.info, it means if users restart MySQL, these rules will lose.
So if users wantn't their replication filter rules lose, they should write the rules in my.cnf.

Users can set rules by 2 ways:
1. Online SET command, "SET connection_name.replication_filter_settings = rules;".
2. In my.cnf, "connection_name.replication_filter_settings = rules".

If no connection_name in my.cnf, this rule will apply for ALL replication connection.
If no connetion_name in SET statement, this rull will apply for default_connection_name.

sql/sql_class.h

@@ -47,6 +47,7 @@
 
 class Reprepare_observer;
 class Relay_log_info;
+class Rpl_filter;
 
 class Query_log_event;
 class Load_log_event;
@@ -1588,6 +1589,9 @@ public:
   /* Slave applier execution context */
   Relay_log_info* rli_slave;
 
+  /* Used to SLAVE SQL thread */
+  Rpl_filter* rpl_filter;
+
   void reset_for_next_command(bool calculate_userstat);
   /*
     Constant for THD::where initialization in the beginning of every query.