Enhance the ioctl toolbox command

1) Implement documented but unimplemented read-only option.
2) Allow standard input to be used as the <device> by passing
   "-".  On some devices, opening the device has side effects.
   Allowing standard input can prevent this by using a sequence
   of something like:

      # Open the device on file descriptor 3
      exec 3<> /dev/something
      ioctl -d - 0 0 <&3
      ioctl -d - 1 0 <&3
      dd if=myfile >&3
      # Close file descriptor 3
      exec 3>&-

Change-Id: If17ac3cffa7ccb159051550724b4ce7d8efa5feb
Signed-off-by: Scott Anderson <saa@android.com>