Merge solver code with static interface

- Breaks backwards compat solver code with last version. Concurrent broke backwards compat because of race conditions with rng, but single is now broken too, despite it being 2x faster (!!!!)
- Literally twice as fast as Rust now in single thread
- Concurrent doesn't work yet, deadlocks somewhere..?

Solver/Crafty/NodeScores.cs

@@ -9,10 +9,17 @@ public struct NodeScores
     public float MaxScore;
     public int Visits;
 
-    public void Visit(float score)
+    public void VisitConcurrent(float score)
     {
         Intrinsics.CASAdd(ref ScoreSum, score);
         Intrinsics.CASMax(ref MaxScore, score);
         Interlocked.Increment(ref Visits);
     }
+
+    public void Visit(float score)
+    {
+        ScoreSum += score;
+        MaxScore = Math.Max(MaxScore, score);
+        Visits++;
+    }
 }