switch coordinates to global 'Coord' type

src/logic/move.rs

@@ -1,11 +1,11 @@
 use super::board_value::BoardValueMap;
-use crate::repr::{Board, Piece, Winner};
+use crate::repr::{Board, Coord, Piece, Winner};
 use lazy_static::lazy_static;
 
 #[derive(Clone, Debug)]
 pub struct Move {
     /// Coordinates (i, j) of the move (if it exists)
-    pub coord: Option<(usize, usize)>,
+    pub coord: Option<(Coord, Coord)>,
 
     /// [`Board`] state after move is made
     pub board: Board,
@@ -41,7 +41,7 @@ lazy_static! {
 
 impl Move {
     pub fn new(
-        coord: Option<(usize, usize)>,
+        coord: Option<(Coord, Coord)>,
         board: Board,
         color: Piece,
         agent_color: Piece,