SPSA NN Final Layer for 12k iterations

[jhonnold]

Bench: 2999259

Tune still ongoing, merging at 12k iterations for TCEC deadline

Elo   | 17.23 +- 5.18 (95%)
SPRT  | 60.0+0.60s Threads=1 Hash=64MB
LLR   | 2.90 (-2.25, 2.89) [0.00, 2.50]
Games | N: 4136 W: 1053 L: 848 D: 2235
Penta | [1, 389, 1088, 584, 6]
http://chess.grantnet.us/test/39475/

Earlier test at 6k iterations

Elo   | 10.99 +- 4.34 (95%)
Conf  | 60.0+0.60s Threads=1 Hash=64MB
Games | N: 6074 W: 1535 L: 1343 D: 3196
Penta | [3, 635, 1577, 811, 11]
http://chess.grantnet.us/test/39447/