Now checks to see if a custom template file exists

You can now use a custom template file on a per-post basis.  

Here's how it works:

When you go to /blog/example-post-slug, it will first check to see if there's a file with that exact slug name + .html (in this case example-post-slug.html) in the /blog/ folder of your site.  If so, it'll use that template; if not, it will use the default _single.html template.

You can try it out by finding an existing blog post, then creating a template called [whatever-that-post-slug-is].html with some random text, and putting it into the /blog/ folder.  Browse to that blog post and you'll see your random text.