Hotfix for rare opportunity bugs

v1.3.0.10
- Fixed bugs resulting from two opportunities being completed in the same end turn sequence and one requiring a player choice but being stuck behind the other.
- Fixed bugs resulting from an opportunity being chosen too quickly.
- Fixed games of 1000+ turns not being loadable from save files.
- Fixed city sprites sometimes being slightly blurred after resetting turn.
- Fixed issues with the app icon on Mac OS.