Bump dependency on ExtensionClass to match current release.

CHANGES.rst

 Changelog
 =========
 
-4.0.4 (unreleased)
-------------------
+4.1 (unreleased)
+----------------
 
+- Bump dependency on ``ExtensionClass`` to match current release.
 
 4.0.3 (2014-11-02)
 ------------------
@@ -13,7 +14,7 @@ Changelog
 4.0.2 (2014-11-02)
 ------------------
 
-- Include *.rst files in the release.
+- Include ``*.rst`` files in the release.
 
 4.0.1 (2014-10-30)
 ------------------

setup.py

@@ -52,7 +52,7 @@ setup(
                            include_dirs=['include', 'src']),
                  ],
     install_requires=[
-        'ExtensionClass >= 4.0a1',
+        'ExtensionClass >= 4.1a1',
         'zope.interface',
     ],
     include_package_data=True,