Add security enhancements. See: https://blog.miguelgrinberg.com/post/cookie-security-for-flask-applications

Make flask respect https! :D See: https://stackoverflow.com/questions/14810795/flask-url-for-generating-http-url-instead-of-https/37842465#37842465

Remove ugly workaround for scheduler function. Now the current app_context is used, instead of creating a new app instance.