url: metadatum doesn't work with title: datum in posts

[equwal]

Essentially this:

;;;;;
title: Short Bio
url: bio.html
format: md
;;;;;

Should probably generate a file called bio.html with the title Short Bio, but instead generates short-bio.html and apparently throws away the url: datum. Not a huge issue, just not "the right thing" in my opinion. I just used a .page instead.

[equwal]

I resolved this in my pull request here: #170

Works fine.