• Improvements to the graph thanks to @Naphthalin:
• The graph now draws two horizontal lines. When using centipawns, these lines correspond to pawn values of -1 and +1, while for winrates they correspond approximately (not exactly) to 25% and 75%. Thus, when the game is close the graph will fall in between those lines.
• The graph is now based on centipawns - apparently this is better, even for Leela.
• Extreme centipawn values (e.g. +20 or +40) will be drawn as basically the same, since they are. This allows more resolution for the critical values where the game is in doubt.