Move to a single setup.py file

[jwiggins]

Closes #440

This brings all the extension building into the single top-level setup.py script.

Some changes:

• No more support for 32-bit OSX systems. That ship has sailed.
• No more ALWAYS_32BIT_WORKAROUND for 64-bit machines with g++ < 4.0
• The macport extension, used for Wx 2.6 support, is not longer built.
• The --compiler=STR option for setup.py develop has been removed.
• The custom clean and build_py commands are gone, as is the explicit use of numpy distutils.

NOTE: The sdist looks like it might be broken.
NOTE: This conflicts pretty massively with #392

[kitchoi]

Offline discussion: We may want to consider this as a proof-of-concept given the nontrivial conflicts with #392.

[kitchoi]

We may want to consider this as a proof-of-concept given the nontrivial conflicts with #392.

Sorry that needs a bit more clarification. This PR is considered provisional now. We need a resolution about #392 first.

[jwiggins]

Finally. The installation is failing because of the .py files generated by SWIG are not copied:

[...]
adding 'kiva/agg/__init__.py'
adding 'kiva/agg/_agg.cpython-36m-x86_64-linux-gnu.so'
adding 'kiva/agg/_plat_support.cpython-36m-x86_64-linux-gnu.so'
adding 'kiva/agg/tests/__init__.py'
[...]

(You should see kiva/agg/agg.py and kiva/agg/plat_support.py in the list of files)

Just need to figure out how to get SWIG-generated .py files into the distribution and this should be working.

(The exact same problem as described here: https://stackoverflow.com/questions/64638474/pythons-setuptools-doesnt-include-auto-generated-swig-python-files)

[jwiggins]

Found an answer: https://stackoverflow.com/a/21236111

[jwiggins]

This PR has now integrated the changes from #392 and is ready for review!

[rahulporuri]

LGTM. I tested this locally (windows, python 3.6 env) - with and without wheel in the environment - and the instllation went without a hitch.

I could mostly follow the changes between the deletions and the additions - but I trust the CI.

Thanks again @jwiggins for this crucial work.

[jwiggins]

Out of an abundance of caution, I diffed the SDISTs between this branch and master and found a couple changes that needed to be made.

[jwiggins]

Thanks for the review!

[rahulporuri]

Out of an abundance of caution, I diffed the SDISTs between this branch and master and found a couple changes that needed to be made.

Thank you. Not sure why that didn't occur to me :/

[jwiggins]

Not sure why that didn't occur to me

Not enough painful memories to draw from?