Use pre-increment also for native types

Now that we use pre-increment on enums, it
make sense, for code style uniformity, to
swith to pre-increment also for native types,
although there is no speed difference.

No functional change.

src/timeman.cpp

@@ -155,7 +155,7 @@ namespace {
     int thisMoveImportance = move_importance(currentPly) * slowMover / 100;
     int otherMovesImportance = 0;
 
-    for (int i = 1; i < movesToGo; i++)
+    for (int i = 1; i < movesToGo; ++i)
         otherMovesImportance += move_importance(currentPly + 2 * i);
 
     float ratio1 = (TMaxRatio * thisMoveImportance) / float(TMaxRatio * thisMoveImportance + otherMovesImportance);