Suggestion: double number scroller

Great! I'd probably put the original menu in a function, and then pass that function in, so:

function showMainMenu() {
  E.showMenu({ ...
     'Time': function () {showDoubleIntPicker("Title",{
         back: showMainMenu,
         ...
     }
}); 
}

Because maybe someone doesn't want to call your picker from a menu, but they want to call it direct from some other part of their app.