DBUG_ macro cleanup
buffer boundary cleanup
This changeset, although not fully tested, works for me better than 
anything I've had so far, including what is in the repository. I will 
push it unless something crashes while I am writing this :-)


mysql-test/r/rpl000014.result:
  updated result
mysql-test/r/rpl000015.result:
  updated result
mysql-test/r/rpl000016.result:
  updated result
mysql-test/r/rpl_log.result:
  new result
mysys/mf_iocache.c:
  DBUG_ cleanup
mysys/mf_iocache2.c:
  DBUG_ fix
sql/log.cc:
  added relay_log_space_limit
sql/mysqld.cc:
  relay_log_space_limit
sql/slave.cc:
  relay_log_space_limit
sql/slave.h:
  relay_log_space_limit
sql/sql_class.h:
  relay_log_space_limit
sql/sql_repl.cc:
  fixed buffer overrun bug