george/prediction_tracker: Manage and score predictions on arbitrary topics. @ 5e786fc98ff6f3b215bdf0fb18d38a6e7c4638a8

George C. Privon 3c82548c80 define canceled predictions as outcome of -1		5 éve
..
create_database.rkt	976166a797 improve require formatting	6 éve
scoring_rules.rkt	7d3b4d3c4a type annotations, more appropriate computation of log score	6 éve
update_predictions.rkt	3c82548c80 define canceled predictions as outcome of -1	5 éve