Whenever a stream is killed, send a notification for that stream if a
notification agent has been specified. If no username is specified,
simply list the session ID.
Although argparse should be smart enough to handle this in any order,
it's generally easier for us poor humans to read the arguments if the
unstructured one is the last argument. Re-order the listing to make this
clearer.
Use the Session created at the start of the script for all requests,
instead of creating a new one for some of them (which doesn't inherit
the settings set on it at the start).
Create a new function get_user_activity that returns the same data
get_activity originally did and use that in main. get_activity now
actually follows the name and gets all activity on the server.
