Optimize konami code so that it actually will check if order is correct before final validation

[augbog]

Taking a look at the code

    // if first button isn't up, return
    if (keypresses.length == 0 && key != 38) {
      return;
    // if valid konami code character and keypresses available
    } else if (keypresses.length < 10 && /37|38|39|40|65|66/.test(key)) {

Ideally rather than validating a correct konami code character, it should verify if the order of the codes is entered correctly. The way it is now, if the user hits up and then hits any key that is a valid konami character i.e. up 10 times, it will still go through and try to validate. We can optimize it by simply going through a stack of the valid keypresses and fail the whole thing if its wrong.