Removing unneeded from __future__ import statements.

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

ebook_converter/ebooks/conversion/plugins/docx_input.py

@@ -1,12 +1,9 @@
-#!/usr/bin/env python2
-# vim:fileencoding=utf-8
-from __future__ import absolute_import, division, print_function, unicode_literals
+from ebook_converter.customize.conversion import InputFormatPlugin, OptionRecommendation
+
 
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from ebook_converter.customize.conversion import InputFormatPlugin, OptionRecommendation
-
 
 class DOCXInput(InputFormatPlugin):
     name        = 'DOCX Input'