[Plugin: Co-Authors Plus] Co-authors order when duplicate post

The solution here would actually be to preserve the order of taxonomy terms in Duplicate Post plugin.

1. In duplicate-post-admin.php, find duplicate_post_copy_post_taxonomies() function (line 344 in Duplicate Posts 1.1.2).
2. Find this code:

   $post_terms = wp_get_object_terms($id, $taxonomy);
   for ($i=0; $i<count($post_terms); $i++) {
   	wp_set_object_terms($new_id, $post_terms[$i]->slug, $taxonomy, true);
   }

3. Replace with:

   $post_terms = wp_get_object_terms($id, $taxonomy, array( 'orderby' => 'term_order' ));
   $terms = array();
   for ($i=0; $i<count($post_terms); $i++) {
   	$terms[] = $post_terms[$i]->slug;
   }
   wp_set_object_terms($new_id, $terms, $taxonomy, false);