Improved King Safety values

From an SPSA-session on king safety.

STC:
ELO: 3.21 +-2.1 (95%) LOS: 99.8%
Total: 40000 W: 8181 L: 7812 D: 24007

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 47765 W: 8091 L: 7785 D: 31889

Bench: 8589262

Resolves #241

src/evaluate.cpp

@@ -91,7 +91,7 @@ namespace {
   // Evaluation weights, indexed by evaluation term
   enum { Mobility, PawnStructure, PassedPawns, Space, KingSafety };
   const struct Weight { int mg, eg; } Weights[] = {
-    {289, 344}, {233, 201}, {221, 273}, {46, 0}, {324, 0}
+    {289, 344}, {233, 201}, {221, 273}, {46, 0}, {322, 0}
   };
 
   #define V(v) Value(v)
@@ -186,15 +186,15 @@ namespace {
   // index to KingDanger[].
   //
   // KingAttackWeights[PieceType] contains king attack weights by piece type
-  const int KingAttackWeights[] = { 0, 0, 8, 4, 4, 1 };
+  const int KingAttackWeights[] = { 0, 0, 7, 5, 4, 1 };
 
   // Bonuses for enemy's safe checks
   const int QueenContactCheck = 89;
-  const int RookContactCheck  = 72;
-  const int QueenCheck        = 51;
-  const int RookCheck         = 38;
-  const int BishopCheck       = 5;
-  const int KnightCheck       = 16;
+  const int RookContactCheck  = 71;
+  const int QueenCheck        = 50;
+  const int RookCheck         = 37;
+  const int BishopCheck       = 6;
+  const int KnightCheck       = 14;
 
   // KingDanger[attackUnits] contains the actual king danger weighted
   // scores, indexed by a calculated integer number.
@@ -412,10 +412,10 @@ namespace {
         // attacked and undefended squares around our king and the quality of
         // the pawn shelter (current 'score' value).
         attackUnits =  std::min(74, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them])
-                     + 9 * ei.kingAdjacentZoneAttacksCount[Them]
+                     + 8 * ei.kingAdjacentZoneAttacksCount[Them]
                      + 25 * popcount<Max15>(undefended)
-                     +  10 * (ei.pinnedPieces[Us] != 0)
-                     - mg_value(score) / 8
+                     +  11 * (ei.pinnedPieces[Us] != 0)
+                     - mg_value(score) * 31 / 256
                      - !pos.count<QUEEN>(Them) * 60;
 
         // Analyse the enemy's safe queen contact checks. Firstly, find the
@@ -891,7 +891,7 @@ namespace Eval {
 
   void init() {
 
-    const double MaxSlope = 8.5;
+    const double MaxSlope = 8.7;
     const double Peak = 1280;
     double t = 0.0;