Real Building Upgrades

Works with September 2019 Patch. Building Upgrades to: - Vanilla buildings (including UBs) - all except ones enabled by beliefs (the game doesn't allow to build more than 1 in a Holy City). - DLCs (if active): Tlachtli, Sukiennice, Basilikoi Paides, Prasat. - Rise & Fall: Food Market, Shopping Mall, Ferris Wheel, Aquarium, Aquatics Center, Ordu, Tsikhe. - Gathering Storm: Coal, Oil and Nuclear Power Plants, Hydroelectric Dam, Marae, Thermal Bath, Grand Bazaar. How does it work? - Each Building can be upgraded and since there are (usually) 3 levels of base buildings, there are also 3 levels of Upgrades. Their characteristics and parameters depend on their level (see below). - Each Building Upgrade has the same icon as base building with a distinctive plus sign added . - A Building Upgrade becomes available usually after researching a tech/civic that follows a tech/civic that grants the base building. This represents the idea that a building has to be constructed and used for some time before any upgrades can be applied. - All unique Buildings also have Upgrades. - The Upgrades are quite powerful but very expensive in terms of maintenance costs. It's by design, they are supposed to rather exclusive buildings, not seen all-around. Upgrades to Level 1 Buildings - provide 50% of base building yields, - some upgrades of early buildings also have unique properties or yields from improvements or resources, - cost approx. 45% of base building, Maintenance Cost = 1, - Hangar is here an