Built-in pricing functions now appear in the marketplace and leaderboard

The public marketplace and the Elo Index leaderboard were empty until a provider listed a function. They now show eight of Last Price's own built-in pricing functions, including the Jale optimizers, cost-plus pricing and the A/B test assigner. Each one is labelled as built-in by Last Price, so you can tell it apart from a third-party provider's listing.

The leaderboard ranks them by the same method as any other listing, from real catalog data only. A function with no recorded latency is no longer scored as the fastest on the board: its speed shows as no data until it has been timed.