Python 3 on Cylc repository master branch

[Hilary Oliver]

Exciting news to report:

The master branch of the Cylc source repository on GitHub now contains a functioning Python 3 Cylc with ZeroMQ network layer, and (warning!) no GUI.

Next up (very soon) Python packaging (pip) ... which is now feasible, without the old PyGTK GUI. And, over the rest of 2019 we are building the new web tech infrastructure and UI around this.

Anyone cloning Cylc with git, rather than installing an official release, needs to be aware of this.

Ongoing maintenance of cylc-7.8 (for Python 2) will continue on the "7.8.x" branch in the repository.

Regards,

Hilary