New python versions supported + version bump

[m-stefanski]

Passes all the tests, except for 3.3 (which is not supported by Travis-CI now):

https://travis-ci.org/github/m-stefanski/memunit/builds/737105589

[coveralls]

Coverage decreased (-19.6%) to 80.42% when pulling f4b1dbe on m-stefanski:master into e1f459e on mschwager:master.

[m-stefanski]

This is very weird, here are Travis-CI results I got:

https://travis-ci.org/github/m-stefanski/memunit/builds/737105589

Please review them manually. It would be great to get higher Python versions support upstream.

Ah, I see that coverage on your repo was only reported 1 file:

----------- coverage: platform linux, python 3.6.3-final-0 -----------
Name                      Stmts   Miss  Cover
---------------------------------------------
lib/memunit/__init__.py      36      0   100%

At the same time coverage for my PR was done on all python files:

----------- coverage: platform linux, python 3.6.7-final-0 -----------
Name                      Stmts   Miss  Cover
---------------------------------------------
lib/memunit/__init__.py      36      0   100%
setup.py                      9      9     0%
tests/test_memunit.py        98     19    81%
---------------------------------------------
TOTAL                       143     28    80%

[mschwager]

Nice! Since 3.4 and 3.5 are EOL let's remove those as well. And we can add 3.9-dev to TravisCI for 3.9 support 👍

[m-stefanski]

Done. I am closing this PR and opening new with:

feat: support for Python 3.9 added, 3.4, 3.5 dropped

https://travis-ci.org/github/m-stefanski/memunit/builds/737328218