fixed backwards compatibility

These changes affect the settings of hue node through the message input.
msg.lamp sets the lamp ID
msg.color sets the lamp color (e.g., msg.color="DF0101" will set the
color to red)
msg.brightness sets the lamp brightness (e.g., msg.brightness=50)
msg.payload is used to se the lamp status (on/off/alert) (e.g.,
msg.payload="alert" will flash the Lamp once)

msg.topic can be still used to set the color (compatibility with
previous versions)