Extended replication to allow extra columns added last on slave
as compared with table on master.


mysql-test/extra/rpl_tests/rpl_row_tabledefs.test:
  Testing that replication can handle extra extra columns on slave.
mysql-test/r/rpl_row_tabledefs.result:
  Result file change
sql/Makefile.am:
  Adding new files.
sql/field.cc:
  Implementing missing Field_bit::set_default()
sql/field.h:
  Implementing missing Field_bit::set_default()
sql/log_event.cc:
  Extending unpack_row() and replace_record() to handle the case when there are more columns
  on the slave than on the master. Especially handle BIT columns correctly.
  Using newly introduced table_def class to perform comparison.
sql/log_event.h:
  Adding field to table_map_log_event. Changing prototype for do_prepare_row().
sql/mysql_priv.h:
  Adding include guards
mysql-test/t/rpl_row_tabledefs.test:
  New BitKeeper file ``mysql-test/t/rpl_row_tabledefs.test''
sql/rpl_utility.cc:
  New BitKeeper file ``sql/rpl_utility.cc''
sql/rpl_utility.h:
  New BitKeeper file ``sql/rpl_utility.h''