Weiss 1.3

Since version 1.2 released 3 months ago Weiss has gained almost 100 self-play elo:

10+0.1
+4516 -2170 =3776
Elo difference: 79.26 +- 5.39

60+0.6
+4236 -1519 =4261
Elo difference: 96.67 +- 5.21

Major changes:

King Safety (Thanks to No4b)
Retuned evaluation
Improved history heuristic