Actually save preference on checkbox change

src/main/java/org/cryptomator/ui/vaultoptions/MasterkeyOptionsController.java

@@ -46,6 +46,11 @@ public class MasterkeyOptionsController implements FxController {
 		}
 	}
 
+	@FXML
+	public void initialize() {
+		useTouchIDheckbox.selectedProperty().bindBidirectional(vault.getVaultSettings().useTouchID);
+	}
+
 	@FXML
 	public void changePassword() {
 		changePasswordWindow.vault(vault).owner(window).build().showChangePasswordWindow();