CAN between nodes, Node 2 Servo and LED

CAN between nodes tested by sending a joystick position from Node 1 to Node 2.
Node 2 servo uses the Servo class from Arduino
LED score count should maybe be removed: Rather poll the LED (and other inputs received over CAN, eg joystick), and send a CAN message to Node 1 when the game is over / score has changed.
Node 2 uart code moved to separate file.
Node 2 CAN loopback test needs to be moved/removed.