Include alter hook for entity id selection (patch included)

By adding a drupal_alter hook after the $ids array is built in the function og_clone_get_group_content_ids you can allow developers to optionally add or remove items to clone. The default behavior is to clone every entity it finds which may not be ideal with some types of content (yet cloning capabilities are excellent overall).

Patch to follow along with documented usage to remove certain content types.