Fix: Ensure $args values are set in get_terms()

After the get_terms() method is defined in line 293 use wp_parse_args() to ensure $args values exist:

function get_terms( $terms, $taxonomies, $args ) {
	$args = wp_parse_args( $args, array(
		'orderby' => '',
		'order' => ''
	) );

https://wordpress.org/plugins/custom-taxonomy-sort/