change file ending to `.rst` for readme and changelog to get proper github rendering

setup.py

@@ -21,7 +21,7 @@ def read(*rnames):
     return open(os.path.join(os.path.dirname(__file__), *rnames)).read()
 
 long_description=(
-        read('README.txt')
+        read('README.rst')
         + '\n' +
         'Detailed Documentation\n'
         '**********************\n'
@@ -50,7 +50,7 @@ long_description=(
         + '\n' +
         read('src', 'zc', 'buildout', 'distribute.txt')
         + '\n' +
-        read('CHANGES.txt')
+        read('CHANGES.rst')
         + '\n' +
         'Download\n'
         '**********************\n'