Atlas autosave

[Philip Taylor]

To avoid data loss, Atlas ought to auto-save maps every n minutes (maybe 5 or so) into a new file (don't overwrite the file the user is really editing). Ideally it would also detect when the game is failing an assertion or crashing etc, and attempt to save the current progress at that point too. It should keep multiple previous versions (maybe 10 or so), so you can recover if it corrupts the latest save or if you realise you accidentally deleted all your units half an hour ago. The option to load an autosave should be hard to miss (perhaps a "open autosave" in the File menu or something), and should show all the autosaves and the time they were saved and the original name of the map being edited.