Added new script to logout all users along with their buddies

[kedar2a]

Added new script to logout all users along with their buddies:

• doc/deployer/logout_all_users.py
• Logging out user and making buddies free(if added any).

---

TEST:

• Log in from multiple browsers/sessions.
• Go to shell python manage.py shell and run following:
  • execfile("../doc/deployer/logout_all_users.py")
• All user's should be log out.
• Repeat same with buddies.
  • After running script to log out all user's with buddies, try to add same buddies in new user session, it should work.