AI tweaks for better targeting

Resolved  - can no longer (temporarily) alter queue in multiplayer in between turns

Resolved  - ultra-rare 'destroy civilian unit before attack' crash

Fixed bad spread of starting positions

row/col are now 1:1 for all tiles, so each int row/col pair has a corresponding x/y pair

chore: Simplified hex coord math - part 2

chore: Simplified hex coord math - part 1

Terrain-Specific Natural Wonder Sprite Support  - By OptimizedForDensity

By vegeta1k95:
- Generify hasGoldToBuy -> hasStatToBuy + fix condition 
- City Screen improvements 
- Fix crash when attacking city with disabled overlays 
- LanguagePickerScreen sorting: English > system lang > percent complete 
- PolicyScreen: branch progress + fix spectator 

Gradle update, offerButton.isEnabled = false in initial  - By lishaoxia1985

By Gualdimar:
- Suggestion: Collapsible tutorial tasks 
- Bigger header on policy and mod screens 
- Fixed completing the "Found city" tutorial by AI