Creation commands

[davidhassell]

Move creation_commands methods from cf-python to cfdm, as mentioned in NCAS-CMS/cfdm#53

Companion PR to NCAS-CMS/cfdm#82

[sadielbartholomew]

Re-triggering the CI tests here (via open-close) now that NCAS-CMS/cfdm#82 has been merged such that the creation commands have become available to cf-python from that, where they were removed in this PR, such the tests should pass unless further work needs to be done to get the right end-to-end behaviour.

I've observed an e2e pass locally so expect a pass unless there are issues on Mac OS platforms.

[sadielbartholomew]

Interestingly there are a couple of CI failures (plus one test failure probably unrelated since we've seen it before, which I will look into), both on test_docstring. Locally they also fail when I run them separately (python test_docstring.py), but they pass if run as part of python run_tests.

(Next week at normal working hours) it would be good to see if you see the same locally, David. It is certainly possible I am doing something silly, but I may not be...

Otherwise I will leave this to you. The test failures look simple to resolve. Thanks.

[sadielbartholomew]

Oh, it looks like you have already solved the pair of test failures in NCAS-CMS/cfdm#83. 👍

[davidhassell]

Ah yes - sorry I forgot to mention that one. I think we can merge, now.