This patch introduces a new (non-visible) `Mounted` class, to be used by the AI instead of `Cavalry`. The advantages of this include:
* cavalry can be used by auras and technology specifically for true cavalry units
* camels, chariots, elephants could be separated from cavalry templates
* mods can introduce zebras, unicorns, pegasi, //whatever// without having to label them with a Cavalry class
* necessary for the AI to be able to train (Briton) war dogs and (Mauryan) elephant archers (which does //not// mean they will train them; merely they could, in theory)
[EDIT]: CitizenSoldier vs Champion is a false dichotomy; this patch replaces it with !Champion vs Champion.