Power switch not staying on
Seems like the switch is resetting itself back to the off state even thought the computer is still on.

Line 38-40:

``` javascript
setTimeout(function() {
  this._service.setCharacteristic(Characteristic.On, false);
}.bind(this), 30000);
```

Any particular reason that is there? Why not leave the switch on, it already assumes that the wol packet was sent successfully. Maybe run a periodic ping to set the actual state?
