Java binding for rs-fsrs, WIP.
see example
see Makefile
make java_run
make api more friendly.
ideal style
FSRS fsrs = new FSRS();
Card card = new Card();
ScheduledCards scheduled_cards = fsrs.schedule(card, Instant.now());
Card updatedCard = scheduled_cards.selectCard(Rating.Easy);
System.out.println(updatedCard.getLog().toString());