Docs/manual.texi:
  Updated replication section
mysql-test/r/null_key.result:
  Added test UPDATE/DELETE with IS NULL on unique key
mysql-test/t/null_key.test:
  Added test UPDATE/DELETE with IS NULL on unique key
mysys/Makefile.am:
  Removed -f from $CP as this is not portable
  Fixed rule for testhash
sql/field.cc:
  Safety fix
sql/opt_range.cc:
  Fixed bug with UPDATE/DELETE on UNIQUE key which could be NULL
sql/opt_range.h:
  Fixed bug with UPDATE/DELETE on UNIQUE key which could be NULL