* Updated .travis.yml to fix PEP 440 warnings
* Fixed twine calls
We were getting test failures on multiple branches in
`test_server.py`. I first investigated a warning message
popping up in every test run:
```
PEP440Warning,
/home/travis/virtualenv/python3.5.2/lib/python3.5/site-packages/pkg_resources/__init__.py:2510: PEP440Warning: 'setuptools (git-0.4.0)' is being parsed as a legacy, non PEP 440, version. You may find odd behavior and sort order. In particular it will be sorted as less than 0.0. It is recommend to migrate to PEP 440 compatible versions.
```
Moving the installation of setuptools, pip, sphinx, and tox
into the `install` key for Travis resolved that issue, but
`test_server.py` tests were still failing. It turns out that
Twine 1.7.0 added support for SSL cert specification and,
in the process, changed the call signature for the `upload`
and `register` internal methods.
This PR fixes the calls so that they align with Twine's new
function signature. Note that tests now fail on Twine <1.7.0,
so I have also updated the dev requirements file.
