The function set_lights() sets station-lighting to the state STATE.
Legal state values are the symbolic constants ON and OFF.
The initialisation of the library sets the state to
OFF.
On successful completion the value SUCCESS is returned, otherwise the
value FAILURE.
int get_lights(void);
The function get_lights() returns the state currently set
by the last call to the function set_lights().
On successful completion either ON or OFF is returned,
otherwise the value FAILURE.