Merge pull request #160 from plone/update-pytz-DateTime

update to latest pytz 2015.7 and DateTime 4.0.1

versions.cfg

@@ -10,16 +10,15 @@ AccessControl = 3.0.12
 ExtensionClass = 4.1.2
 Acquisition = 4.2.2
 # More memory efficient version, Trac #13101
-DateTime = 3.0.3
+DateTime = 4.0.1
+pytz = 2015.7
 Products.BTreeFolder2 = 2.14.0
 # Override until ztk is updated
 Sphinx = 1.3.4
 # required for recent z3c.form and chameleon
 zope.pagetemplate = 3.6.3
 # Support for more complex catalog queries
 Products.ZCatalog = 3.0.2
-# Several tests rely on an old-style pytz release:
-pytz = 2013b
 
 
 # Build tools