[core,board] Move board::piece to core

Break up types in core into finer grained modules.
Update all the imports.

board/src/position/builders/move_builder.rs

@@ -1,13 +1,10 @@
 // Eryn Wells <eryn@erynwells.me>
 
 use crate::{
-    piece::{PlacedPiece, Shape},
-    position::flags::Flags,
-    r#move::Castle,
-    Color, MakeMoveError, Move, Piece, Position,
+    position::flags::Flags, r#move::Castle, sight::SightExt, MakeMoveError, Move, Position,
 };
 use chessfriend_bitboard::BitBoard;
-use chessfriend_core::{Direction, Square};
+use chessfriend_core::{Color, Direction, Piece, PlacedPiece, Shape, Square};
 
 /// A position builder that builds a new position by making a move.
 #[derive(Clone)]
@@ -244,7 +241,8 @@ impl<'p> From<&'p Position> for Builder<'p, NoMove> {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::{r#move::Castle, MoveBuilder, PositionBuilder};
+    use crate::{position, r#move::Castle, MoveBuilder, PositionBuilder};
+    use chessfriend_core::piece;
 
     #[test]
     fn move_white_pawn_one_square() -> Result<(), MakeMoveError> {

board/src/position/builders/position_builder.rs

@@ -1,12 +1,11 @@
 // Eryn Wells <eryn@erynwells.me>
 
 use crate::{
-    piece::{PlacedPiece, Shape},
     position::{flags::Flags, piece_sets::PieceBitBoards},
     r#move::Castle,
-    Color, MakeMoveError, Move, Piece, Position,
+    MakeMoveError, Move, Position,
 };
-use chessfriend_core::{Rank, Square};
+use chessfriend_core::{piece, Color, Piece, PlacedPiece, Rank, Shape, Square};
 use std::collections::BTreeMap;
 
 #[derive(Clone)]
@@ -130,6 +129,7 @@ impl Default for Builder {
 #[cfg(test)]
 mod tests {
     use crate::PositionBuilder;
+    use chessfriend_core::piece;
 
     #[test]
     fn place_piece() {

board/src/position/diagram_formatter.rs

@@ -40,7 +40,8 @@ impl<'a> fmt::Display for DiagramFormatter<'a> {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::Position;
+    use crate::{position, Position};
+    use chessfriend_core::piece;
 
     #[test]
     #[ignore]

board/src/position/flags.rs

@@ -1,6 +1,7 @@
 // Eryn Wells <eryn@erynwells.me>
 
-use crate::{r#move::Castle, Color};
+use crate::r#move::Castle;
+use chessfriend_core::Color;
 use std::fmt;
 
 #[derive(Clone, Copy, Eq, Hash, PartialEq)]
@@ -40,7 +41,8 @@ impl Default for Flags {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::{r#move::Castle, Color};
+    use crate::r#move::Castle;
+    use chessfriend_core::Color;
 
     #[test]
     fn castle_flags() {

board/src/position/piece_sets.rs

@@ -1,11 +1,7 @@
 // Eryn Wells <eryn@erynwells.me>
 
-use crate::{
-    piece::{Piece, PlacedPiece},
-    Color,
-};
 use chessfriend_bitboard::BitBoard;
-use chessfriend_core::Square;
+use chessfriend_core::{Color, Piece, PlacedPiece, Square};
 
 #[derive(Debug, Eq, PartialEq)]
 pub enum PlacePieceStrategy {

board/src/position/pieces.rs

@@ -1,9 +1,8 @@
 // Eryn Wells <eryn@erynwells.me>
 
 use super::Position;
-use crate::piece::{Color, Piece, PlacedPiece, Shape};
 use chessfriend_bitboard::BitBoard;
-use chessfriend_core::Square;
+use chessfriend_core::{Color, Piece, PlacedPiece, Shape, Square};
 
 pub struct Pieces<'a> {
     color: Color,
@@ -74,9 +73,8 @@ impl<'a> Iterator for Pieces<'a> {
 
 #[cfg(test)]
 mod tests {
-    use super::*;
-    use crate::piece::{Color, Piece, Shape};
     use crate::{Position, PositionBuilder};
+    use chessfriend_core::{piece, Color};
     use std::collections::HashSet;
 
     #[test]

board/src/position/position.rs

@@ -2,15 +2,14 @@
 
 use super::{flags::Flags, piece_sets::PieceBitBoards, Pieces};
 use crate::{
-    move_generator::Moves,
-    piece::{Color, Piece, PlacedPiece, Shape},
+    move_generator::{MoveSet, Moves},
     position::DiagramFormatter,
     r#move::Castle,
-    sight::Sight,
+    sight::SightExt,
     Move,
 };
 use chessfriend_bitboard::BitBoard;
-use chessfriend_core::Square;
+use chessfriend_core::{Color, Piece, PlacedPiece, Shape, Square};
 use std::{cell::OnceCell, fmt};
 
 #[derive(Clone, Debug, Eq, PartialEq)]
@@ -268,8 +267,8 @@ impl fmt::Display for Position {
 
 #[cfg(test)]
 mod tests {
-    use crate::{position, Castle, Color, Position};
-    use chessfriend_core::Square;
+    use crate::{position, test_position, Castle, Position};
+    use chessfriend_core::{piece, Color, Square};
 
     #[test]
     fn piece_on_square() {