GameOver Screen: "Exit to Menu" button doesn't work

[yeslayla]

Issue description:

It looks like a not implemented error

Fix can be included in #105

[yeslayla]

I was able to get the 'Exit to Menu' button to work. Currently pushed to feature/options. I'll make a PR for it once the requirements for #105 are implemented.

Ended up not being too bad. main.end_game() will now function to return everything to main menu. Though, it does throw out some errors in the debugger that will need to be cleaned up eventually.

If errors are not fixed alongside this issue, a new issue should be created.