Supporting conda 4.4+

[jakirkham]

As of conda 4.4, the preferred way to activate/deactivate a conda environment is conda activate/conda deactivate. This also requires sourcing <ROOT>/etc/profile.d/conda.sh on Unix where <ROOT> is the base of the conda installation. Would be good to update the activation/deactivation steps in the kernels here to support conda 4.4+.

ref: https://github.com/conda/conda/releases/tag/4.4.0

[jankatins]

Updating to conda 4.4+ has some not so nice sideeffects: 'conda' not found in path. probably because conda is now a shell function and not a command anymore and also because my jupyter notebook systemd service hasn't activated the root environment :-(

This might help here: http://tech.akom.net/archives/93-Getting-a-systemd-unit-to-read-your-.bashrc-file-for-its-environment.html

[Cadair]

probably because conda is now a shell function and not a command anymore

🙀

[jankatins]

This might be an easier way to get the activated environment variables:
https://github.com/tox-dev/tox-conda/pull/1/files#diff-3960d5009402e509ed9ea4aa24b71dfaR55

For the "conda not found" problem: there is now a 'conda_exe' environment variable (at least on unix), which we should try first...

[jayagami]

So.. the problem remains