Handling of loading crashes

[Fabio]

This is a feature that, if possible, would make the game look much more professional.
When loading a game, if it is not compatible with the current pakset, instead of crashing the program should go back too the loading menu or to the new world menu with an error message like "impossible to load the saved game selected". How to achieve this? Maybe taking a memory snapshot before starting loading and in case of crash restoring the memory to that point.

Similarly, starting the game, if there is a choice of paksets and the selected one is corrupted, the program should crash to the pakset choice menu.