tests: Add ability to test different expected outputs based on Python version. Similar to the previous change, there was also a change in what gets escaped by `urllib.parse.quote` (as in: the tilde sign ('~') stopped being escaped). So now we need to be able to test different outputs in the tests, yay again.

---
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