PV refutation penalty

Extra penalty for PV move in previous ply when it gets refuted.

STC:
LLR: 4.49 (-2.94,2.94) [-1.50,4.50]
Total: 41094 W: 7889 L: 7620 D: 25585

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,6.00]
Total: 12304 W: 1967 L: 1811 D: 8526

Bench: 8373608

Resolves #386

src/search.cpp

@@ -553,7 +553,7 @@ namespace {
  goto moves_loop;
  }
 
- moveCount = quietCount = 0;
+ moveCount = quietCount =  ss->moveCount = 0;
  bestValue = -VALUE_INFINITE;
  ss->ply = (ss-1)->ply + 1;
 
@@ -826,6 +826,8 @@ namespace {
  }
  else
  ++moveCount;
+
+ ss->moveCount = moveCount;
 
  if (RootNode)
  {
@@ -934,6 +936,7 @@ namespace {
  if (!RootNode && !SpNode && !pos.legal(move, ci.pinned))
  {
  moveCount--;
+ ss->moveCount = moveCount;
  continue;
  }
 
@@ -1425,8 +1428,8 @@ namespace {
  cmh.update(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus);
  }
 
- // Extra penalty for TT move in previous ply when it gets refuted
- if (is_ok((ss-2)->currentMove) && (ss-1)->currentMove == (ss-1)->ttMove && !pos.captured_piece_type())
+ // Extra penalty for PV move in previous ply when it gets refuted
+ if (is_ok((ss-2)->currentMove) && (ss-1)->moveCount==1 && !pos.captured_piece_type())
  {
  Square prevPrevSq = to_sq((ss-2)->currentMove);
  HistoryStats& ttMoveCmh = CounterMovesHistory[pos.piece_on(prevPrevSq)][prevPrevSq];

src/search.h

@@ -47,6 +47,7 @@ struct Stack {
  Depth reduction;
  Value staticEval;
  bool skipEarlyPruning;
+ int moveCount;
 };
 
 /// RootMove struct is used for moves at the root of the tree. For each root move