Binder

[breuera]

The cloud-version of the FA16-branch and the master-branch doesn't work for me. Here's the log for the FA16-branch:

[...]
Step 9/13 : RUN jupyter contrib nbextension install --user
 ---> Running in f6a10854d5c2
Traceback (most recent call last):
  File "/home/jovyan/.local/bin/jupyter-contrib", line 10, in <module>
    sys.exit(main())
  File "/opt/conda/lib/python3.7/site-packages/jupyter_core/application.py", line 266, in launch_instance
    return super(JupyterApp, cls).launch_instance(argv=argv, **kwargs)
  File "/opt/conda/lib/python3.7/site-packages/traitlets/config/application.py", line 656, in launch_instance
    app = cls.instance(**kwargs)
  File "/opt/conda/lib/python3.7/site-packages/traitlets/config/configurable.py", line 412, in instance
    inst = cls(*args, **kwargs)
  File "/home/jovyan/.local/lib/python3.7/site-packages/jupyter_contrib_core/application.py", line 27, in __init__
    self._refresh_subcommands()
  File "/home/jovyan/.local/lib/python3.7/site-packages/jupyter_contrib_core/application.py", line 43, in _refresh_subcommands
    get_subcommands_dict = entrypoint.load()
  File "/opt/conda/lib/python3.7/site-packages/pkg_resources/__init__.py", line 2433, in load
    self.require(*args, **kwargs)
  File "/opt/conda/lib/python3.7/site-packages/pkg_resources/__init__.py", line 2456, in require
    items = working_set.resolve(reqs, env, installer, extras=self.extras)
  File "/opt/conda/lib/python3.7/site-packages/pkg_resources/__init__.py", line 791, in resolve
    raise VersionConflict(dist, req).with_context(dependent_req)
pkg_resources.ContextualVersionConflict: (traitlets 4.3.2 (/opt/conda/lib/python3.7/site-packages), Requirement.parse('traitlets>=5.0'), {'nbconvert'})
Removing intermediate container f6a10854d5c2
[...]

The PR contains some changes to get the repo working.

[ketch]

Thanks @breuera ! This looks reasonable to me, but we'll wait for comments from @rjleveque since he is the expert on this.

[rjleveque]

Looks good to me and I confirmed that it works on binder, while the old version no longer worked.

Thanks @breuera!

[rjleveque]

Note: I have also merged this in to the FA16 branch so that binder launches properly from the link on the book's website.