Nibabel does not "pip install" with six

[GaelVaroquaux]

pip installing nibabel under python2 installs a non working nibabel because of missing six in the requirements. As a result, the CI is broken on nilearn:
nilearn/nilearn#1900

Steps to reproduce:

1. Create a clean python2.7 virtualenv
2. "pip install nibabel"
3. Try importing nibabel

Results in

  File "/home/varoquau/tmp/clean_venv/local/lib/python2.7/site-packages/nibabel/testing/__init__.py", line 29, in <module>
    from six.moves import zip_longest
ImportError: No module named six.moves

[effigies]

Ah, thanks for tracking this down. I suspect this happened because of the switch to setuptools from distutils.

[GaelVaroquaux]

Thank you so much for being that fast in addressing this issue. I am impressed.