Don't silently ignore unrecognized configuration options

[Hornwitser]

When configuring Factorio servers it's easy to make a typo, or use the wrong name for a setting. When you start the server there's no feedback on whether everything in config was understood. This leads to problems that could have easily been avoided if the server admin was made aware of the mistake.

This is particularly troublesome when importing old configurations from previous versions that contains options that have been removed or renamed.

[Impatient]

+10