cpython: add support for mac os x

[myselfhimself]

[myselfhimself]

Clang / llvm V6 + openmp through cibuildwheel seem to be on the right track: https://github.com/dtschump/gmic-py/commit/2b16c1b6aae514f2ec146602e6add4f28d6f514c/checks?check_suite_id=368488912

[myselfhimself]

We do have Mac OS X binary builds online now on PyPI.. Time for testers to try out basic scenarios on their machines.. https://pypi.org/project/gmic/2.8.1.dev1/#files

Let me close this when we have found some real user testing and confirming the good news

[myselfhimself]

Let us target 2.8.3 and bump the version to something without a dev* prefix

[myselfhimself]

bumping here a259e8f996c48c1da30866d0f1b9081b74cc57d0

[myselfhimself]

Add python34 support ?

[myselfhimself]

python 3.4 has reached end of life not doing anything for it Delocate in cibuildwheel did not seem to work fully as libomp and fftw seem to have to be installed for it to work. See related CI job in gmic-blender to add those missing libs.

[myselfhimself]

Seen on xgboost and libGBM projects: libomp must be written as a requirement in a documentation, because delocate does not process it for now

[myselfhimself]

I want a colleague to test..

[myselfhimself]

Any mac users reading this should head to the py-gmic MacPorts project to get fresh gmic-py releases, with properly enabled and linked OpenCV and OpenMP support.

I will probably will not provide mac OS x releases anymore for gmic-py; @Schamschula is an excellent maintainer for the macports gmic-py (named py-gmic) versions.

One last TODO item before closing

• [ ] document (in the README and readthedocs website) recommended exclusive use of MacPorts for installing gmic-py on MacOS + hints on building oneself