Assorted Bugfixes for V1.0

A few bugfixes, with more to come. Crucially fixes the long-standing achievement bug for "Stone Cold". Bug fixes will be merged onto the beta-branch in the next patch (as well as sent over to the Itch build). Details: Gameplay: -If Mammon's initial settlement would be too small (<40 population) it is increased in size (minor change to climate and adding population to meet new cap) -"Fuel the fire" unrest boosting challenge is no longer valid when there are no positive influences, but has a minimum gain to avoid zero-gain situations (it rounds all positive influences up) Bugfixes: -Fix occasional issue with "repeat challenge" button on challenge completion popup -FINALLY solved the bugged "Stone Cold" achievement (Discord user "Valorous Heart" had actually found the cause a month ago, I just missed the report) -Fixed issue with sacrificial dagger not working -Fixed enshadowment% in nations view