existing "iolight timer" code in the hard drive code. If an LED is registered
with the "auto-off" flag, the device only needs to turn on the LED to indicate
data transfer. The LED timer in the gui code turns it off after 0.5 seconds if
it is not actived by another transfer. Added this feature to all network
devices.
- TODO #1: implement this feature in the USB host controllers
- TODO #2: the unused timer in the hard drive code could be used for the
emulation of seek functions