GUI Wrapper VI - The Implementation, Part II

-GUI wrapped HighscoreUI.
-Removed the Replay option from HighscoreUI.
-Amiga500GUISkin has a custom layer nobox. This is to remove the box
from toggle, which wasnt useful for labels. Affects LevelEditor and
Options
-Removed redundant code for sliders in GUIManager
-Mapped string and Texture correctly in Options
-To prevent the UI's from derping, changed mapping of Perceptual Volume
from 1,2,3 to 0,1,2