MenuBackend
Provide an easy way of making menus.

moveRelativeLevels()
Move relatively in the menu hierarchy level.

moveToLevel()
Move to a specific menu hierarchy level.

fireItemChangedEvent()
Fire a callback for change.

getRoot()
Get the root of this menu.

getCurrent()
Get the current item of this menu.

use()
Use an item, will fire use event.

moveBack()
Move back in the menu structure, will fire move event.

moveUp()
Move up in the menu structure, will fire move event.

moveDown()
Move down in the menu structure, will fire move event.

moveLeft()
Move left in the menu structure, will fire move event.

moveRight()
Move right in the menu structure, will fire move event.