ignores distance penalty until first hit found

[csunday95]

• also added some checks for null/undefined values that are ignored in deployed version, but detected as errors in the development server

• incremented version to 0.0.22

[Amphitryon0]

Can you elaborate a bit on why this is wanted? It's quite rare that users don't get sub-20/sub-19, and the distance penalty is intended to make similar speed–consistency tradeoffs at all probability scales, including with no hits. Perhaps we could decrease the distance penalty only when there are no hits and there have been several misses, to increase the win rate in this case without giving slower shots to most users. Alternatively, we could try to create a better movement time metric than L1 distance, which could increase win rate without increasing average movement time (or decrease average movement time without decreasing the win rate).