Allow/Disallow trading for the native trader

[TheRealAyCe]

I think it would be cool to be able to manage warehouse trader preferences separately for the native trader.

[crudelios]

This has been requested a lot actually, but right now the issue is ui-related: there's no space on the window to add new walker types!

We never figured out the best solution for this (though to be fair, we never discussed it thoroughly), so the change keeps being postponed.

[TheRealAyCe]

Yeah, I can see the problem. Love this mod though, it actually made me play through the campaign again! Took a while to figure out fast roads (noob trap, they aren't actual roads!) and cart depots, but they make food management so much cleaner!