Custom maps are retained when starting a new game from an old one

Spies "evacuate" correctly from destroyed cities

Spectators can see the building list again

By unciv-loof:
- Confirmation popup before breaking promise not to spy 
- ConstructImprovementInstantly now clears tile improvement queue 

Fixed issue with units selection in city - By ValeraShimchuck

By Ambeco:
- AI: Minimize movement before attacking
- PathingMap can now also BFS, taking moveCost into consideration