Inescapable loop choosing class when no classes exist.

[toonarmycaptain]

Currently, one may try to create a new chart before creating any classes, and the menu prompts the user to select a class, and no input will escape the loop (since there are no classes).
A guard should be here, prompting the user to create a new class, or/and a way to go back/cancel. O just print an error message, suggest first creating a class, and return user to main menu.