Added history — though still need to be checked thoroughly

Sources/Engine/Pieces/Piece.swift

@@ -53,7 +53,7 @@ public enum Kind: String, CaseIterable {
 	}
 }
 
-public class Piece {
+public class Piece: Hashable {
 	#warning("TODO: To be removed, handle everything through the delegate")
 	internal weak var board: Board?
 	public internal(set) var color: Color
@@ -94,6 +94,7 @@ public class Piece {
 			}
 
 		}
+		delegate?.addPieceToTarget(self, target: pos)
 		return true
 	}
 
@@ -102,4 +103,30 @@ public class Piece {
 		self.position = pos
 		self.color = col
 	}
+
+	/// Two pieces are equal when they share the same kind, color and position
+	public static func == (lhs: Piece, rhs: Piece) -> Bool {
+		return lhs.kind == rhs.kind && lhs.color == rhs.color
+			&& lhs.position == rhs.position
+	}
+
+	/// Two pieces are not equal when they either do not share the same kind,
+	/// color or position
+	public static func != (lhs: Piece, rhs: Piece) -> Bool {
+		return !(lhs == rhs)
+	}
+
+	/// Checks if tho pieces are similar yet not equal.
+	/// They are considered simmilar if they share the same color and the same kind,
+	/// but differ in position.
+	public static func ~= (lhs: Piece, rhs: Piece) -> Bool {
+		return lhs.kind == rhs.kind && lhs.color == rhs.color
+			&& lhs.position != rhs.position
+	}
+
+	public func hash(into hasher: inout Hasher) {
+		hasher.combine(kind)
+		hasher.combine(position)
+		hasher.combine(color)
+	}
 }