Require six>=1.4.0

Fix #18

Author: Andrey Fedoseev

setup.py

@@ -35,7 +35,7 @@ def read(fname):
  ],
  keywords=["sass", "scss", "less", "css", "coffeescript", "javascript"],
  requires=[
- "six",
+ "six(>=1.4.0)",
  ],
  tests_require=[
  "mock",

static_precompiler/utils.py

@@ -4,7 +4,7 @@
 from django.utils.encoding import smart_str, smart_bytes
 from django.utils.importlib import import_module
 # noinspection PyUnresolvedReferences
-from six.moves.urllib import parse as urllib_parse
+from six.moves import urllib_parse
 from static_precompiler.exceptions import UnsupportedFile
 from static_precompiler.settings import MTIME_DELAY, POSIX_COMPATIBLE, COMPILERS, \
  STATIC_URL, CACHE_NAME