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

George C. Privon 23e8a801ca re-format(indent) code		%!s(int64=5) %!d(string=hai) anos
..
create_database.rkt	976166a797 improve require formatting	%!s(int64=6) %!d(string=hai) anos
scoring_rules.rkt	7d3b4d3c4a type annotations, more appropriate computation of log score	%!s(int64=6) %!d(string=hai) anos
update_predictions.rkt	23e8a801ca re-format(indent) code	%!s(int64=5) %!d(string=hai) anos