- reduced requirements for cultural retinues.

Small adjustments:
- slightly reduced retinues constant costs,
- slightly reduced retinues reinforce costs,
- added missing retinue upfront costs increase.

Fixed vanilla version infantry tier 5 retinue which had reversed numbers of troops: 400 LI and 100 HI instead of the other way around.
Typo pointed out by alexerleo - cheers mate.

Final fix for nomadic retinues. You will no longer see duplicate retinue types available for hire. Turning retinues off will still allow nomads to hire them.

Fixed, entirely unintentional, crippling of nomadic nations with retinues turned off, by allowing them to hire retinue units as they are designed as nomad mechanic.