Use perpage and count field in get_comments

Test on any device of your choice.

1. On a master site. Navigate to the site blog.
2. Search a blog post with more than 15 comments or, add it yourself:
   1. Enter the coments of a blog post. Add 16-20 comments.
3. Check total number of comments is displayed on the blog post with format Comments (number).
4. Now repeat 1 and 2 steps on a 3.6 site.
5. Check the number of comments has a limit on 14 and it shows Comments (14+).