rename volume volid to file to better represent the meaning,

add raw value string to devices,
fix JSON to go naming for device_name vendor_name ... in devices,
bump API version to 0.03

app/model.go

@@ -238,5 +238,7 @@ func (instance *Instance) RebuildDevice(host *Node, deviceid string) error {
 		// sub function assignment not supported yet
 	}
 
+	instance.Devices[InstanceDeviceID(instanceDeviceBusID)].Value = instanceDevice
+
 	return nil
 }