Old save files can't be loaded

[orsinium]

After upgrading to the latest dev version and pressing "continue":

ERROR(app): failed to load save: invalid save file marker

[orsinium]

Probably not a problem to break backward compatibility since there are not many players in the game so far. Just mentioning in case it's not backward compatibility issue but something corrupting the save.

[applejag]

Ah sorry, in v0.1.3 the save file format was changed by #21, which is incompatible with the old one.

In hindsight I should've done a bigger version bump and be more clear about it in release notes, and perhaps added a error log saying "yo your save file is not supported, sorry" just to be less confusing