Removed old imports used for python 2

src/sessions/__init__.py

@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 """ this package contains code related to Sessions.
 In TWBlue, a session module defines everything a social network needs to be used in the program."""
-from __future__ import unicode_literals
 # let's define a global object for storing sessions across the program.
 sessions = {}