[board] Clean up a bunch of build errors

Fix imports to refer to core and bitboard crates.
Fix some API use errors.

board/src/position/builders/move_builder.rs

@@ -4,8 +4,9 @@ use crate::{
     piece::{PlacedPiece, Shape},
     position::flags::Flags,
     r#move::Castle,
-    BitBoard, Color, MakeMoveError, Move, Piece, Position,
+    Color, MakeMoveError, Move, Piece, Position,
 };
+use chessfriend_bitboard::BitBoard;
 use chessfriend_core::{Direction, Square};
 
 /// A position builder that builds a new position by making a move.

board/src/position/builders/position_builder.rs

@@ -1,14 +1,13 @@
 // Eryn Wells <eryn@erynwells.me>
 
 use crate::{
-    bitboard::BitBoardBuilder,
     piece::{PlacedPiece, Shape},
     position::{flags::Flags, piece_sets::PieceBitBoards},
     r#move::Castle,
-    BitBoard, Color, MakeMoveError, Move, Piece, Position,
+    Color, MakeMoveError, Move, Piece, Position,
 };
+use chessfriend_core::{Rank, Square};
 use std::collections::BTreeMap;
-use chessfriend_core::Square;
 
 #[derive(Clone)]
 pub struct Builder {
@@ -109,8 +108,8 @@ impl Builder {
 
 impl Default for Builder {
     fn default() -> Self {
-        let white_king_square = Square::king_starting_square(Color::White);
-        let black_king_square = Square::king_starting_square(Color::Black);
+        let white_king_square = Square::E1;
+        let black_king_square = Square::E8;
 
         let pieces = BTreeMap::from_iter([
             (white_king_square, piece!(White King)),

board/src/position/piece_sets.rs

@@ -2,8 +2,9 @@
 
 use crate::{
     piece::{Piece, PlacedPiece},
-    BitBoard, Color,
+    Color,
 };
+use chessfriend_bitboard::BitBoard;
 use chessfriend_core::Square;
 
 #[derive(Debug, Eq, PartialEq)]
@@ -125,7 +126,7 @@ impl PieceBitBoards {
 
 impl FromIterator<PlacedPiece> for PieceBitBoards {
     fn from_iter<T: IntoIterator<Item = PlacedPiece>>(iter: T) -> Self {
-        let mut pieces = Self::default();
+        let mut pieces: Self = Default::default();
 
         for piece in iter {
             let _ = pieces.place_piece(&piece);

board/src/position/pieces.rs

@@ -2,7 +2,7 @@
 
 use super::Position;
 use crate::piece::{Color, Piece, PlacedPiece, Shape};
-use crate::BitBoard;
+use chessfriend_bitboard::BitBoard;
 use chessfriend_core::Square;
 
 pub struct Pieces<'a> {

board/src/position/position.rs

@@ -7,8 +7,9 @@ use crate::{
     position::DiagramFormatter,
     r#move::Castle,
     sight::Sight,
-    BitBoard, Move,
+    Move,
 };
+use chessfriend_bitboard::BitBoard;
 use chessfriend_core::Square;
 use std::{cell::OnceCell, fmt};