ci: Use Python 3.6 everywhere

.appveyor.yml

@@ -11,8 +11,9 @@ environment:
     - TESTENV: pylint
 
 install:
-  - C:\Python27\python -u scripts\dev\ci\appveyor_install.py
-  - set PATH=%PATH%;C:\Python36
+  - '%PYTHON% -m pip install -U pip'
+  - '%PYTHON% -m pip install -r misc\requirements\requirements-tox.txt'
+  - 'set PATH=%PATH%;C:\Python36'
 
 test_script:
-  - C:\Python34\Scripts\tox -e %TESTENV%
+  - '%PYTHON% -m tox -e %TESTENV%'

.travis.yml

@@ -41,7 +41,9 @@ matrix:
     #   env: TESTENV=py35 OSX=yosemite
     #   osx_image: xcode6.4
     - os: linux
-      env: TESTENV=pylint
+      env: TESTENV=pylint PYTHON=python3.6
+      language: python
+      python: 3.6
     - os: linux
       env: TESTENV=flake8
     - os: linux

scripts/dev/ci/appveyor_install.py

@@ -1,41 +0,0 @@
-#!/usr/bin/env python2
-# vim: ft=python fileencoding=utf-8 sts=4 sw=4 et:
-
-# Copyright 2015-2017 Florian Bruhin (The Compiler) <mail@qutebrowser.org>
-
-# This file is part of qutebrowser.
-#
-# qutebrowser is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# qutebrowser is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with qutebrowser.  If not, see <http://www.gnu.org/licenses/>.
-
-# pylint: skip-file
-
-"""Install needed prerequisites on the AppVeyor.
-
-Note this file is written in python2 as this is more readily available on the
-CI machines.
-"""
-
-from __future__ import print_function
-
-import subprocess
-
-
-def pip_install(pkg):
-    subprocess.check_call([r'C:\Python34\python', '-m', 'pip', 'install', '-U',
-                           pkg])
-
-
-print("Installing tox")
-pip_install('pip')
-pip_install(r'-rmisc\requirements\requirements-tox.txt')