2.0.0 - Goodbye Screen & Thnx for all the fish

Summary

This release denotes the removal of Screen to keep the server process running, this script now relies on starting the process in the background and keeping track of a pid rather than the guesswork involved previously to parse the output of ps.
Relying on a pid (tracked in the ${PIDFILE}) also allowed for a simpler systemd unit example.

Input redirection now means one can send any input to the server simply by writing to the ${FIFO} pipe, something the newly added command ./factorio cmd uses to send chat messages and commands to the server.

Upgrading

With the introduction of a pid file/pipe, please first stop your server before you start using this version.

I suggest you clone the github repo and review the recent changes in config.example, if your base config was cloned long ago it might even be better to simply take a backup of your current and start with a fresh copy based on config.example