Demands/Requests from other civs do not stop other events registering

Better 'Pay to improve CS resource'

Seed pillage randomness to avoid save-scum

Modding: 
- Added misspelling tests for uniqueTo for buildings, units and improvements
- Triggerable uniques on promotions only activate once when added on creation
- Beliefs can have AI decision modifiers, and do in base rulesets

Finish city-state quests upon acquiring great person

Prevent AI placing units near citadels - by EmperorPinguin