Use TOV2 as a (semi)periodic timer tick, and use it to debounce the pushbutton input
Disable ADC in this sketch to save power
Use Timer2 ticks to trigger 'IDLE' output after 5 secs of inactivity
Start implementing a low-power idle mode

This puts the device into a low-power sleep when IDLE is returned from
process_inputs(). The sleep mode is only entered when there is no input
to be processed, and the RCN network is also idle. When entering the
low-power sleep, we first blink the red LED three times, to tell the user
that we're going to sleep. We then disable the PWM outputs, and call
Sleepy::powerDown() to enter the low-power sleep mode.

Running this sketch on a 3.3V JeeNode v6 yields a current of ~0.54mA in
the sleep mode (~= 1.8mW)
Turn off RCN radio in sleep mode

Running this sketch on a 3.3V JeeNode v6 yields a current of ~0.16mA in
the sleep mode (~= 0.53mW)
Disable more stuff in sleep mode. Only use pushbutton (or reset) to wake up.

Also extend idle delay to 10 secs,