0.9.28b Save Manager

[h2]New Feature "Save Manager"[/h2]
Recently, many players have reported issues with lost save files, so I made this tool.

• The Save Manager can be accessed from the bottom right corner of the main menu, where it will list all your save files on the computer.
  
• Now you can freely switch, create new, or copy your save files, with an automatic backup saved every day.
  
• Already unlocked all vehicles but still craving more? Start a new save file and relive the joy of meeting the students for the first time!
  

• Fixed a bug where destroying all anti-aircraft vehicles in the raid mission still wouldn't complete the level.