writing DROP and CREATE TRIGGER to binlog, disabling binlogging
of substatements, testing.


mysql-test/r/rpl_sp.result:
  result update
mysql-test/t/rpl_sp.test:
  removing useless lines, plus testing replication of triggers
sql/sql_trigger.cc:
  trigger can be used to destroy slave, so only SUPER can create it by default.
  If create|drop goes ok, binlog CREATE TRIGGER and DROP TRIGGER.
sql/sql_trigger.h:
  disable binlogging of substatements of triggers (even if now triggers
  can't do updates)