Drop support for Python 2.6.

.travis.yml

 language: python
 sudo: false
 env:
-    - TOXENV=py26
     - TOXENV=py27
     - TOXENV=pypy
     - TOXENV=py33

CHANGES.rst

 Changes
 =======
 
-4.1.1 (unreleased)
+4.2.0 (unreleased)
 ------------------
 
-- TBD
+- Drop support for Python 2.6.
 
 4.1.0 (2015-05-22)
 ------------------

setup.py

@@ -84,7 +84,7 @@ else:
 
 
 setup(name='zope.container',
-      version='4.1.1.dev0',
+      version='4.2.0.dev0',
       author='Zope Foundation and Contributors',
       author_email='zope-dev@zope.org',
       description='Zope Container',
@@ -101,7 +101,6 @@ setup(name='zope.container',
           'License :: OSI Approved :: Zope Public License',
           'Programming Language :: Python',
           'Programming Language :: Python :: 2',
-          'Programming Language :: Python :: 2.6',
           'Programming Language :: Python :: 2.7',
           'Programming Language :: Python :: 3',
           'Programming Language :: Python :: 3.3',

tox.ini

 [tox]
-envlist = py26,py27,pypy,py33,py34,py27-zodb,pypy-zodb,py27-pure-zodb,docs
+envlist = py27,pypy,py33,py34,py27-zodb,pypy-zodb,py27-pure-zodb,docs
 
 [testenv]
 commands = python setup.py -q test -q