Faction Differentiation Improvements

[Andrettin]

It would be good to have stronger differentiation between the game's civilizations and factions. This could be achieving by adding more civilization/faction-specific upgrades, units and buildings. The purpose of this issue is to gather ideas for that.

• Fyrd upgrade for the Anglo-Saxons (Conscription upgrade class). The Fyrd was a levy which existed in Anglo-Saxon societies, composed largely of infantry. The upgrade could reduce infantry training times. Image reference: [1] (right half)
• Chivalry upgrade for the Franks and Teutons. The upgrade could provide cavalry units with a vs. cavalry bonus.
• Holmgang upgrade for the Norse (Dueling upgrade class). The Holmgang was a sort of judicial duel practiced in Norse society. It could provide infantry units with a vs. infantry bonus, representing that the practice would result in the honing of personal combat skills. Image references: [1] [2]
• Leidang (Leiðangr) upgrade for the Norse (Press Gang upgrade class). Leiðangr was a form of ship levy practiced by the Norse. The upgrade could reduce ship construction times.
• Slinger unit for the Suebi. The Column of Marcus Aurelius depicts Germanic slingers, who were probably Suebi.