Swift 3 compatibility

[samuelclay]

• Updated dependencies
• createSceneWithName now returns the completed scene id (since there's no other way to get it) which required a new type alias for the completion handler
• Added a way to overload the bridge heartbeat delegate so that I can deterministically get the latest scenes
• Changed the Error class to HueError, since calling it the Error class overwrote Apple's own Error class and had broken CoreBluetooth in weird ways.
• Added updateLightStateInScene to bridgeSendAPI