For previous commit I had run only rpl* tests, here the other ones had a 
few surprises. Latest status:
- all tests pass
- all replication tests pass with Valgrind
This is the final-final commit & push.
Doc remains.


client/mysqlbinlog.cc:
  Making remote mysqlbinlog work with the new format of 5.0.0, and still be 
  able to talk to older servers.
  This is a quickfix, but now mysqlbinlog.test passes (mysqlbinlog seems to
  work in Valgrind, too).
mysql-test/r/drop_temp_table.result:
  result update
mysql-test/r/insert_select.result:
  result update
mysql-test/r/mix_innodb_myisam_binlog.result:
  result update
mysql-test/r/mysqlbinlog.result:
  result update
mysql-test/t/mix_innodb_myisam_binlog.test:
  position update
mysql-test/t/mysqlbinlog.test:
  position update
sql/log_event.cc:
  a comment (noticed the problem by watching the results of
  mix_innodb_myisam_binlog.test)