Log Message:
Update py-flask-login to 0.4.0.

Version 0.4.0
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Released on October 26th, 2016

- Fixes OPTIONS exemption from login. #244
- Fixes use of MD5 by replacing with SHA512. #264
- BREAKING: The `login_manager.token_handler` function, `get_auth_token` method
  on the User class, and the `utils.make_secure_token` utility function have
  been removed to prevent users from creating insecure auth implementations.
  Use the `Alternative Tokens` example from the docs instead. #291