Disable infinite load on single-post page

This pull-request can be debated.

Next posts are loaded on every page : 
- homepage
- category page
- single-post page

It should be nice to disable this load on the single-post page. 
- First, there's no reason to get every posts on this page (at best, only related ones, but this is another problem).
- Second, it can become a constraint for some themes. I'm thinking -for example- about getting a meta block with `position: fixed` : if we scroll under the post content, where the posts list was loaded, the block will be above the list. Sure it can be solved with a few CSS/JS, but it shouldn't be a problem first of all.