Added "Save on Quit" prompt

● Added a prompt asking players to save when exiting or returning to the main menu.

● Fixed a bug where a new save would incorrectly load data from another save slot.

● Fixed a bug that prevented tree cutting, as well as saving and quitting the game.

● Fixed a bug where breaking wooden stakes, small stones, etc. prevented saving and quitting.

● Fixed a bug where breaking rubble piles in ruins prevented saving and quitting.