fix resource warnings

setup.py

@@ -19,9 +19,13 @@ from setuptools import find_packages
 
 here = os.path.abspath(os.path.dirname(__file__))
 
+def read(fname):
+    with open(fname) as fp:
+        return fp.read()
+
 try:
-    README = open(os.path.join(here, 'README.txt')).read()
-    CHANGES = open(os.path.join(here, 'CHANGES.txt')).read()
+    README = read(os.path.join(here, 'README.txt'))
+    CHANGES = read(os.path.join(here, 'CHANGES.txt'))
 except:
     README = ''
     CHANGES = ''