updated rotate event to set new position along with the new log


mysql-test/mysql-test-run.sh:
  added --do-test
mysql-test/r/rpl_log.result:
  update for new rotate event format
sql/log_event.cc:
  rotate event now supports forcing a new position, not just the log
sql/log_event.h:
  clean-up of rotate event, support for position force with rotate event
sql/slave.cc:
  accept position setting from rotate event
sql/sql_repl.cc:
  updates to fake_rotate_event() for the new format