add back pruning

src/logic/future_moves.rs

@@ -94,7 +94,7 @@ impl FutureMoves {
                     }
                 });
 
-            // self.prune_bad_children();
+            self.prune_bad_children();
             self.current_depth += 1;
             if cf.is_break() {
                 println!("extend_layers: early break");