dependency hell

[ejhumphrey]

In attempting to resolve a coverage / pytest-cov dependency issue (the base conda install wasn't leaving things in a working state), I've stepped on an even more annoying dependency problem in Python 3.4: https://travis-ci.com/cosmir/openmic-2018/jobs/146643891

tldr: tensorflow wants an old setuptools (<=39) while everything else is happy to move along to 40+. Thus, I have Questions:

• Do we want to pin setuptools just to appease TF?
• Do we really want to support 3.4?

@bmcfee I assume you have opinions?

[ejhumphrey]

btw, to keep marching along, I'm going to disable 3.4 builds in the interim, since everything else is fine (minus a bunch of stdout vomit about deprecation warnings from TF)

[bmcfee]

We don't need to support 3.4. Upgrading within the 3 series doesn't break anything, so it's not the same headache that 2<->3 is.

[ejhumphrey]

sounds good, will uncomment and remove forevvver

[bmcfee]

After merging #43 I can knock this one out by migrating the packaging up to the modern spec (setup.cfg, pyproject.toml, etc).