split_from and diag use iterators not vectors

src/complexagent.rs

@@ -248,7 +248,7 @@ pub struct ComplexAgent {
 
 impl ComplexAgent {
     pub fn new(color: Piece) -> Self {
-        const MAX_DEPTH: usize = 6;
+        const MAX_DEPTH: usize = 7;
         Self {
             color,
             future_moves: FutureMoves::new(color, MAX_DEPTH),