Adding number of play-outs for moves candidates in json reporting

[pnprog]

Before: {"Q16": 0.492} After: {"Q16": [0.492, 15935]}

If you prefer, I can make something more verbose like this instead: After: {"Q16": ["winrate": 0.492, "playouts": 15935]}

[lemonsqueeze]

If you prefer, I can make something more verbose like this instead: After: {"Q16": ["winrate": 0.492, "playouts": 15935]}

The first one is nice, thanks.