fixed bugs in new IO_CACHE code so that the old calls work
fixed shutdown bug
clean-up of mysql-test-run


include/my_sys.h:
  fixes for IO_CACHE
mysql-test/mysql-test-run.sh:
  fixed missing \ bug
  added --skip-gdb-magic to skip Sergei's automatic mysql_parse break
  do not delete the breakpoint in command - it crashes gdb sometimes
mysys/mf_iocache2.c:
  rc_pos->write_pos in my_b_seek for WRITE_CACHE
sql/mysqld.cc:
  fixed shutdown bug when singals DO break read introduced by the fix for 
  when they don't.
sql/repl_failsafe.cc:
  fixed memory leak