Update wpml-comments-merging.php

- remove the "remove_filter"/"add_filter" from WPML
- use $sitepress->get_active_languages(); instead of icl_get_languages()
- use get_option('comment_order') instead of "ASC"
- use $otherpost = get_post($otherID); instead of an IF
- user $count += instead of $count = $count +