fixes for IO_CACHE
need to pull Monty's fixes - this is not final, will not be pushed


include/my_sys.h:
   IO_CACHE fixes
mysql-test/mysql-test-run.sh:
  manager clean-up
mysys/mf_iocache.c:
  IO_CACHE fix
sql/mysqld.cc:
  more debug messages
tools/mysqlmanager.c:
  added pid-file