prep for release

CHANGES.txt

 CHANGES
 =======
 
-Unreleased
-----------
+4.0.0 (2013-08-18)
+------------------
 
 - Avoid reading excess random bytes when setting up an auth_digest session.
 

setup.py

@@ -13,6 +13,7 @@
 ##############################################################################
 """Setup
 """
+version = '4.0.0'
 from setuptools import setup, find_packages
 import os
 import sys
@@ -98,7 +99,7 @@ long_description = (
     open('CHANGES.txt').read()
     )
 setup(name="ZEO",
-      version='4.0.0b1',
+      version=version,
       description = long_description.split('\n', 2)[1],
       long_description = long_description,
       url = 'https://pypi.python.org/pypi/ZEO',