Comment pager broken when adding comments to a node from ctools.

The Problem:

https://www.drupal.org/node/2433923

This basically says, If adding comments via a ctools plugin the pager is broken. This is the case but goes a bit deeper. If you try to add comments to a node outside of the default and you call comment_get_thread() There isn't a way to allow passing in a pager id so you can have more than one pager without the ids screwing up.

The Proposed Solution:

Adding an argument to comment_get_thread() to allow passing in a pager id:

// Allows setting a specific pager id.
  if (isset($pager_id)) {
    $query->element($pager_id);
  }

This is extremely helpful if adding multiple comments with pager to a node via: ctools plugins or any other way.

Thanks,

--Scott