routing: Fix breakages with routing on some versions of Python. Finally figured what happened with change 6baa94da8b16 (this is a Mercurial hash by the way if you're looking at the Git mirror). Between Python 3.6 and 3.7 there was a change where the percent sign ('%') went from being escaped by `re.escape` to _not_ being escaped. So now we need to use different regex patterns dependin on the Python version, yay.

---
no_kitchen: true
args: init .
files:
    - config.yml
---
no_kitchen: true
args: init myblog
files:
    - myblog/config.yml
---
args: prepare page foobar
files:
    - kitchen/pages/foobar.md
---
args: prepare post -d 2017/01/08 new-post
files:
    - kitchen/posts/2017-01-08_new-post.md