Correct encoding bug producing unnecessary newlines on Python 3.6, Windows 10

runestone/__main__.py

@@ -55,6 +55,12 @@ def init():
     paver_final = paver_stuff.decode('utf-8') % conf_dict
     config_final = config_stuff.decode('utf-8') % conf_dict
 
+    # On Windows, Python 3.6, the bytes read from ``template_base_dir`` and ``config_stuff`` contain Windows-style ``\n\r``. Unfortunately, `resource_string <http://setuptools.readthedocs.io/en/latest/pkg_resources.html#basic-resource-access>`_ does no universal newline support, so these remain intact. When written out, this is changed to ``\n\n``, making the file double-spaced. Python 3's `StringIO <https://docs.python.org/3/library/io.html#io.StringIO>`_ class provides universal newline support, while Python 2's `StringIO <https://docs.python.org/2/library/stringio.html#StringIO.StringIO>`__ doesn't. 
+    if six.PY3:
+        # Per the `TextIOWrapper docs <https://docs.python.org/3/library/io.html#io.TextIOWrapper>`_, ``newline=None`` selects universal newline mode. The Python 3 StringIO_ class's ``newline`` argument works the same.
+        paver_final = six.StringIO(paver_final, newline=None).read()
+        config_final = six.StringIO(config_final, newline=None).read()
+
     with open('pavement.py','w') as pvf:
         pvf.write(paver_final)