Implemented saving to PGN file

+ copyVariations parameter in copy constructors of Board and Log

This procedure still required work in the form of efficiently rewinding
the board to the first position for SAN move extraction and shortening
SAN moves to the smallest possible representation.

test/dev/kske/chess/board/BoardTest.java

@@ -31,7 +31,7 @@ class BoardTest {
 	 */
 	@Test
 	void testClone() {
-		Board clone = new Board(board);
+		Board clone = new Board(board, false);
 		assertNotSame(clone, board);
 		assertNotSame(clone.getBoardArr(), board.getBoardArr());