
travis: * stop using tox * Add Python 3.6 and 3.7-dev * Stop pypy3 (until PyPy3.5 is released) appveyor: * Drop Python 3.4 and add 3.6
travis: * stop using tox * Add Python 3.6 and 3.7-dev * Stop pypy3 (until PyPy3.5 is released) appveyor: * Drop Python 3.4 and add 3.6