Weiss 1.4

Since version 1.3 released 5 months ago Weiss has gained about 160 self-play elo:

STC
+5315 -910 =3775
Elo difference: 164.29 +- 5.56

LTC
+4949 -698 =4353
Elo difference: 157.70 +- 5.18

Major changes:

Additional evaluation terms
Additional pruning heuristics
Improved use of history heuristics

Weiss now expects to play with Syzygy tablebases. Without them, it will probably misevaluate some more drawn endings than before.