Initial Python 3 compatible code

src/fixes/fix_urllib3_warnings.py

@@ -1,8 +1,11 @@
 # -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+from future import standard_library
+standard_library.install_aliases()
 from requests.packages import urllib3
 from requests.packages.urllib3 import fields
 import six
-import urllib
+import urllib.request, urllib.parse, urllib.error
 
 def fix():
  urllib3.disable_warnings()
@@ -19,6 +22,6 @@ def patched_format_header_param(name, value):
             return result
     if not six.PY3 and isinstance(value, six.text_type):  # Python 2:
         value = value.encode('utf-8')
-    value=urllib.quote(value, safe='')
+    value=urllib.parse.quote(value, safe='')
     value = '%s=%s' % (name, value)
     return value