Added command 'replace_column' to mysqltest
client/mysqltest.c:
Added user command replace_column
mysql-test/r/merge.result:
Update of tests
mysql-test/t/innodb.test:
User replace_column to make tests repeatable
mysql-test/t/merge.test:
New tests for testing MERGE tables with multiple databases
scripts/mysql_create_system_tables.sh:
Fixed syntax error
sql/ha_myisammrg.cc:
Allow one to use MERGE tables with tables from different databases
sql/mysql_priv.h:
Added function
sql/sql_parse.cc:
Allow one to use MERGE tables with tables from different databases
sql/sql_show.cc:
Extended append_identifier()