When pre-loading, start with the newest post as the documentation says #55
The help content on the Preloading page states:
"Preloading creates lots of files however. Caching is done from the newest post to the oldest so please consider only caching the newest if you have lots (10,000+) of posts. This is especially important on shared hosting."
This seems a good approach, however currently the code picks post "oldest" first, not "newest". This PR amends things to pick the "newest" posts to preload first.
* The current definition of "newest" or "oldest" is actually based on post ID, and this PR maintains that, albeit swapping the ordering. However ordering by post_modified might actually be better - happy to revise this PR if you agree.