Add login/logout link to Genesis nav

functions.php

//* Add login or logout to menu
add_filter( 'wp_nav_menu_items', 'sp_add_loginout_link', 10, 2 );
function sp_add_loginout_link( $items, $args ) {
	// Change 'primary' to 'secondary' to put the login link in your secondary nav bar
	if ( $args->theme_location != 'primary' )
		return $items;

	if ( is_user_logged_in() ) {
		$items .= '<li class="menu-item right"><a href="'. wp_logout_url() .'">Log Out</a></li>';
	} else {
		$items .= '<li class="menu-item right"><a href="'. site_url('wp-login.php') .'">Log In</a></li>';
	}

	return $items;
}