Add blocking parameter to reboot API call

[hpsin]

DevicePortal.Reboot signature should be modified to Reboot(bool blocking=false), where if blocking ==true, the wrapper pings in the background until the device is updated, at which point the function returns.

[david-c-kline]

there should also be a max time to wait parameter as well. the signature for this feature could turn into: RebootAndWait(TimeSpan maxTimeToWait).

[WilliamsJason]

I like the idea of a RebootAndWait API.

[david-c-kline]

@hpsin , @WilliamsJason Do we still want this? The Windows Mixed Reality Commander (from https://github.com/Microsoft/HoloLensCompanionKit) performs device reboots and uses a periodic heartbeat to determine if the device has restarted.

[hpsin]

Yes, I think this would be a good thing.