Drop Python 2.6 and Python 3.3 support

.travis.yml

 sudo: false  # run travis jobs in containers
 language: python
 python:
-  - 2.6
   - 2.7
-  - 3.3
   - 3.4
   - 3.5
   - 3.6
   - pypy
   - pypy3.5
   - 3.7-dev
-matrix:
-  allow_failures:
-  - python: 2.6
 cache: pip
 install:
   - pip install tox-travis

docs/changelog.rst

@@ -22,6 +22,9 @@ New features
 
 .. _`Issue 86`: https://github.com/berkerpeksag/astor/issues/86
 
+* Dropped support for Python 2.6 and Python 3.3. Even the latest version of pip
+  dropped its support for both of these versions.
+
 Bug fixes
 ~~~~~~~~~
 

setup.cfg

@@ -33,6 +33,7 @@ classifiers =
 zip_safe = True
 include_package_data = True
 packages = find:
+python_requires = >=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*
 
 [options.packages.find]
 exclude = tests

tox.ini

 [tox]
-envlist = py26, py27, py33, py34, py35, py36, pypy, pypy3.5
+envlist = py27, py34, py35, py36, pypy, pypy3.5
 skipsdist = True
 
 [testenv]
@@ -7,4 +7,4 @@ usedevelop = True
 commands = nosetests -v --nocapture {posargs}
 deps =
  -rrequirements-tox.txt
- py2{6,7},pypy: unittest2
+ py27,pypy: unittest2