Added simple close button to tab component

src/dev/kske/chess/ui/GameTabComponent.java

@@ -2,6 +2,7 @@ package dev.kske.chess.ui;
 
 import java.awt.FlowLayout;
 
+import javax.swing.JButton;
 import javax.swing.JLabel;
 import javax.swing.JPanel;
 import javax.swing.JTabbedPane;
@@ -33,6 +34,11 @@ public class GameTabComponent extends JPanel {
 			}
 		});
 
-		// TODO: Add closing button
+		JButton btnClose = new JButton("Close");
+		btnClose.addActionListener((evt) -> {
+			int i = tabbedPane.indexOfTabComponent(GameTabComponent.this);
+			if (i != -1) tabbedPane.remove(i);
+		});
+		add(btnClose);
 	}
 }