18.8.21 final save system fix

Finally got around to fixing the last flaw in the save function: I had already made it so that when you saved it would overwrite any saves in a later chapter in that slot, but only in Slot 1 (whoops) but that's fixed now. Also, you might notice the 'Dev mode' option, don't worry about it, I just got sick of having to play through chapters to test later ones, e.t.c., and it seems silly to go to the effort to hide it just to show it again in my version. I'll probably delete it once the game is finished, but in the mean time there's just a tiny chance that someone will find the password and be able to alter their stats. Oh, the horror. Please tell me of any bugs <3

Patchworked Rainbow