pandoc is producing non-ascii characters

[videlec]

With pandoc installed the setup.py failed because pandoc seems to introduce non ascii characters. Repeating the commands from setup.py

>>> import subprocess
>>> pandoc = subprocess.Popen(['pandoc', 'README.md', '--to', 'rst'], stdout=subprocess.PIPE)
>>> readme = pandoc.communicate()[0]
>>> readme.decode()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 3325: ordinal not in range(128)
>>> readme[3310:3340]
's using Ipython\xe2\x80\x99s ``%%`` `ce'

computer: linux, archlinux
pandoc version 2.0.6
tested on python 2.7.14

See also downstream issue.