Saving and loading the game

[Autofire]

If the user exits a game in progress using the 'X' button, it should save the game state to a file. Upon loading the game, it needs to check for this file. If the file is found, the user should be prompted, asking whether they want to continue the previous game.

If the user does File -> Exit, the game shouldn't save anything.

Tasks

• If the user doesn't exit using File -> Exit, the game should be serialized to a file.
• Upon loading while the save file exists, the user should be asked if the file should be loaded.
• If the user declines, the file should be deleted.
• If the user accepts, the file should be de-serialized, and then the file should be deleted.

Done

The user should be able to resume an interrupted game if they want to.