Removing unneeded from __future__ import statements.

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

ebook_converter/library/__init__.py

@@ -1,14 +1,14 @@
-from __future__ import absolute_import, division, print_function, unicode_literals
+"""
+Code to manage ebook library
+"""
+import os
+
+from ebook_converter.polyglot.builtins import range
+
 
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
-''' Code to manage ebook library'''
-
-
-import os
-from ebook_converter.polyglot.builtins import range
-
 
 def db(path=None, read_only=False):
     from ebook_converter.db.legacy import LibraryDatabase