pip install support

[angerhang]

After the recent update, pip is no longer supported and pip install directly from Github fails with req not found. Do you think we can add pip support back instead of requiring everyone to use miniconda :D

[angerhang]

It turns out that pip -V 10.0.0b2 is not compatible with the current setup.py which throws an error:

(my-env) (bmnn) tsf-444-wpa-2-033:bioNN_EPFL_2018 Hang$ pip install -e git+https://github.com/EPFL-LCN/neuronaldynamics-exercises.git
Could not detect requirement name for 'git+https://github.com/EPFL-LCN/neuronaldynamics-exercises.git', please specify one with #egg=your_package_name
(my-env) (bmnn) tsf-444-wpa-2-033:bioNN_EPFL_2018 Hang$ pip install git+https://github.com/EPFL-LCN/neuronaldynamics-exercises.git
Collecting git+https://github.com/EPFL-LCN/neuronaldynamics-exercises.git
  Cloning https://github.com/EPFL-LCN/neuronaldynamics-exercises.git to /private/var/folders/zv/8tdb08g97ql362y6_p5lk7280000gn/T/pip-req-build-x1j4sW
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/private/var/folders/zv/8tdb08g97ql362y6_p5lk7280000gn/T/pip-req-build-x1j4sW/setup.py", line 2, in <module>
        from pip.req import parse_requirements
    ImportError: No module named req

However, downgrading pip to 9.0.3 resolves this issue. The compatibility should be checked nonetheless.

[seeholza]

@angerhang thanks for bringin this to our attention - I agree we should pick up pip/pypi support again, which was dropped in the last release.
@MarcoLehmann could you please have a look? The comment by @angerhang should provide hints as what to do. If you want I can also have a look.