Check for drive faults

[alexdewar]

One way to fix #692 is to query the controller's alarm status after every move to check whether the move terminated prematurely due to the motor hitting a limit switch. While we're querying the alarm status, we will also obtain information about whether the motor has experienced a drive fault. This seems like useful information to share with the user and happily, we'll be getting it anyway, so it makes sense to do something with it. Probably this should just consist of broadcasting a device error and closing the device.