Removing unneeded from __future__ import statements.

Since we are on Python 3.6 and up, we don't need those anymore.

ebook_converter/polyglot/functools.py

@@ -1,13 +1,8 @@
-#!/usr/bin/env python2
-# vim:fileencoding=utf-8
-# License: GPL v3 Copyright: 2019, Kovid Goyal <kovid at kovidgoyal.net>
-
-from __future__ import absolute_import, division, print_function, unicode_literals
-
 from ebook_converter.polyglot.builtins import is_py3
 if is_py3:
     from functools import lru_cache
 else:
     from backports.functools_lru_cache import lru_cache
 
+
 lru_cache