added philips_hue node

Have added a new hardware node, the philips_hue. It allows access and control of a Philips Hue wireless Lamp bridge. Users can use the node to scan for the IP address of a Hue bridge in the local network and get the list of Lamps registered. In addition, using the node UI or an appropriate msg.payload they can se the status of a Lamp to On/Off and Alert (flashing).
Based on node-hue-api.