Specifies the multiplier applied to Cost of all BuildingTypes owned by this country.
This needs testing
The following section contains information that has not been personally confirmed by the revision's author; readers are encouraged to test it themselves and update the section accordingly.
It is not known what is the relation between this setting and Cost set under the Difficulty sections.
It is not known whether this setting affects all BuildingTypes, or all excluding the ones on the defense tab. (See CostDefensesMult.)
