Cannot trade with civs you're at war with through notification action

Remove city-state construction bonuses from difficulty

By tuvus:
- Espionage Uniques, Buildings and Policy 
- Civs with spies in a foreign cities get some information 

By SomeTroglodyte:
- Fix "Connect road" through Mountains 
- "New game" UI improvements 

Implement Same-majority-religion diplomatic modifier  - By TommasoPetrolito (new contributor!)

AI civilian units consider more triggerable uniques  - By woo1127