Fixes#225. Someone will need to add a `TWINE_PASSWORD` GitHub repository secret that is
a token for `zope.eggbuilder` to upload to zope.interface.
Builds and uploads manylinux32/64/aarch64 wheels.
Builds and uploads Mac wheels.
Builds the docs.
Runs tests with the C extension and without the C extension.
Reports coverage to coveralls.
Has the start of an environment to do linting.
Removes .travis.yml
Turns out that the C extensions build and work fine with PyPy, but don't use them by default. Let them
be forced, though.
Tests needed some refactoring to account for the various permutations.
As per [their blog post of the 27th April](https://blog.readthedocs.com/securing-subdomains/) ‘Securing subdomains’:
> Starting today, Read the Docs will start hosting projects from subdomains on the domain readthedocs.io, instead of on readthedocs.org. This change addresses some security concerns around site cookies while hosting user generated data on the same domain as our dashboard.
Test Plan: Manually visited all the links I’ve modified.
Jason Madden
Jürgen Gmach
Michael Howitz
Nikita Sobolev
Adam Chainz
Felix Yan
Tres Seaver
Marc Abramowitz