Make gradle "run" task run in background.

[joethe]

Either this, or we add a script(s) to manage running and stopping the server.

[joethe]

It's looking like the best way to handle this is actually to just run the server jar using a service.

[joethe]

During the S17 semester, this was handled by simply running the task inside Tmux of Screen.
In the future, though, it might still be worth looking into running it as a service (or some such) as part of the (not implemented at all yet) continuous deployment system.