Fixed multiplayer bugs (double files, turn checker problems) - By Azzurite

By SomeTroglodyte:
- Fix Autocracy Complete bug
- Fix effect of new Beliefs not immediately visible

Fix crashes when a civ does not have a capital - By OptimizedForDensity

By xlenstra:
- Great improvements buildable on removable terrain features

By itanasi:
- Fix Zone of Control
- Assign Population Improvements

By JackRainy:
- Performance improvements
- Better city connection quest check