Ensure server always exits safely

[kegsmr]

At the moment there's no safe way to shutdown the server. So far it hasn't caused any problems, but there is a chance that the server could be in the middle of an important operation when the process is killed.

The best way to ensure the server always exits safely might be to handle the keyboard interrupt and have it trigger the server to cleanup and shutdown.

Note: pretty sure the keyboard interrupt wouldn't work on Windows distributions, but that seems like a Windows problem...