Add Python 3.7, download badge, PEP8 compliance/test

[scivision]

• Add Python 3.7 Travis-CI. This temporarily uses sudo until Travis-CI makes Xenial official released. I have been using this Travis Python 3.7 setup extensively and reliably.
• add PyPi download stat badge
• modernize to use setup.cfg, which has been supported for a couple years and is the modern Python pathway to better Python security via machine-parsable setup files.
• PEP8 compliance / self-test via flake8

Note: Python 3.4 was removed from Travis-CI, but is still tested in AppVeyor. I feel this is acceptable as Python 3.4 is nearing end of life, and 3.4 support has been dropped in 2017 in such popular modules as pandas etc.
In my contributions to core Python, I see that 3.4 requires increasingly awkward workarounds to support, and commonly 3.4 is lightly tested by the Python developers, as in this pull request.
Python 3.4 is thus still a part of this package, just not as extensively tested, as happens with Python itself.

P.S. recursive auto-PEP8 compliance edits can be done by autopep8 -i -r .

[pndurette]

Oh damn, this is fantastic, thank you! I had a Python 3.7 branch 'waiting' for TravisCI. But that does it. And I didn't know about setup.cfg and I'm glad to see it takes a an .md as long_description. So I imagine PyPi is good with that nowadays?

[scivision]

Yes PyPi is fine with Markdown as long as the setup.cfg includes the markdown specification. You can still use RST without that specification, but I started using Markdown because PyPi wasn't liking my more complicated RST, but PyPi was fine with the Markdown.

[scivision]

I added requirements.txt copied from setup.cfg for GitHub's new Python security scan feature. I consider this a temporary workaround, as setup.cfg is trivial to parse and is a standard part of setuptools. I have requested GitHub add setup.cfg to their scan.

[pndurette]

First, ensure that you have checked in a requirements.txt or Pipfile.lock file inside of repositories that have Python code.

Uhm, yeah, that's kinda silly. It doesn't always make sense to ship software with a locked list of dept, especially for libraries..

[scivision]

Yes so either way, if it seems silly to have this requirements.txt just delete it. I hope GitHub will improve the scan in the future.

[pndurette]

Ahh sorry for the delay @scivision, I appreciate this cleanup + CI work across operating systems! I was a bit iffy about the requirements.txt but I see you deleted it and that I suppose it's not an issue anymore with GH's security scan? Either way, I don't really mind, just curious.

[pndurette]

I will bump the release shortly.

[pndurette]

Hmm.. I got some failures to look at too. Things that passed in the PR, but apparently not on master anymore. Some of them seemed intermittent, I couldn't look for too long right now.

[pndurette]

The failures were due to another thing (languages fetching from a new translate.google.com). So had to fix that (and also went to a conference, and then got sick post-conference..).

Released in gTTS 2.0.2 !

Thanks again for not only your crazy good contribution, @scivision, but this is great reference for future/other projects! 💯

[scivision]

Yes I use this general template for over 100 projects. There are some more cleanups possible for testing vis-a-vis tempfile and pytest when I get time.