increase a position's mate score from 23 to 32

[robertnurnberg]

Extensive analysis by @Yery strongly suggests that the shortest mate for 2r1b1Q1/6p1/2P5/5P2/1p2K3/pPp5/n2P4/1B2k3 w - - is longer than 23 moves. The best we found so far is a mate in 32, for which this PR adds the PV. See #52 (comment) for the following analysis:

info depth 89 seldepth 64 multipv 1 score mate 32 nodes 39014129406053 nps 45155242 hashfull 1000 tbhits 0 time 864000003 pv g8e6 e8f7 e6c8 c3d2 b1c2 a2c3 e4e3 a3a2 c8a6 f7e8 c6c7 e8d7 a6d6 d2d1n c2d1 c3d1 e3f3 a2a1q d6e7 e1d2 e7d7 d2c2 c7c8q d1c3 c8c5 a1h1 f3g3 h1c1 d7g7 c2b2 c5f2 b2a3 g7a7 a3b3 f2e3 c1f1 e3e6 b3c2 a7e3 b4b3 e6c6 f1d3 c6g2 d3e2 g2e2 c3e2 e3e2 c2c3 f5f6 b3b2 e2d1 b2b1q d1b1 c3c4 b1c2 c4b5 f6f7 b5b6 f7f8q b6b7 f8b4 b7a6 c2a2

Once this is merged, the number of open positions in #52 will be reduced to five.