Memory + CPU performance improvements

By RobLoach:
- Fix Null Exception in searching Civilopedia 
- Modding: Allow removing Religions and Beliefs 

By SomeTroglodyte:
- Swapping for Escort formation pairs 
- Make Notifications setting "Disabled" useful 

Generic'd Gold from pillaging encampments and cities unique - By PLynx01

Using Renamed Unit Names in Battle Notifications - By GameCobra

Enable espionage by default in new games - By unciv-loof