Removing unneeded from __future__ import statements.

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

ebook_converter/ebooks/mobi/writer2/serializer.py

@@ -1,12 +1,3 @@
-#!/usr/bin/env python2
-# vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:ai
-from __future__ import absolute_import, division, print_function, unicode_literals
-
-__license__   = 'GPL v3'
-__copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
-__docformat__ = 'restructuredtext en'
-
-
 import re
 import unicodedata
 from collections import defaultdict
@@ -21,6 +12,11 @@ from ebook_converter.polyglot.builtins import unicode_type, string_or_bytes
 from ebook_converter.polyglot.urllib import urldefrag
 
 
+__license__   = 'GPL v3'
+__copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
+__docformat__ = 'restructuredtext en'
+
+
 class Buf(BytesIO):
 
     def write(self, x):