added jobs to build binary wheels on linux and OSX

[beniwohli]

This uses the fantastic cibuildwheel to generate wheels for both OSX and Linux. It runs the test suite for every built wheel.

Additionally, added an example setup for pushing the wheels to S3 on tagged commits. These could then be pushed to PyPI. Another option would be to automatically upload the wheels to PyPI.

I have a similar PR in the works for Windows, but am struggling a bit with AppVeyor. I'll open a separate PR once I figured it out.

[coveralls]

Coverage remained the same at 93.399% when pulling 69db1cb on beniwohli:feature/travis-cibuildwheel into a4aeb4c on GrahamDumpleton:develop.

[coveralls]

Coverage remained the same at 93.399% when pulling 7cfb16e on beniwohli:feature/travis-cibuildwheel into a4aeb4c on GrahamDumpleton:develop.

[coveralls]

Coverage remained the same at 93.399% when pulling 7cfb16e on beniwohli:feature/travis-cibuildwheel into a4aeb4c on GrahamDumpleton:develop.

[beniwohli]

@GrahamDumpleton is this something you think would be useful? Anything I could do to get it merged?

[GrahamDumpleton]

Mainly a lack of time over the past few months. I don't know anything about cibuildwheel, and not very conversant at using Travis either, and I feel I probably need to learn more about it first.

Maybe we can jump on Skype some time (just not today as had a tooth pulled earlier today) and quickly discuss it so you can give me a quick run down on what additional things it is doing, how it works with Travis and what other steps needs to be done to get the wheels uploaded to PyPi without requiring too much manual effort.

Basically just comes down to me being comfortable with what it is doing and having a bit of a cheat sheet on what to do if it starts playing up.

[GrahamDumpleton]

Closing this as have shifted builds/tests to GitHub actions and have got help in preparing all that in order to be able to produce both source and binary wheel packages. No too long now hopefully until first release with them.