Refactor|GameMap: Replaced methods for retrieving GameMap's SurfaceSets

- GameMap_DecoratedSurfaces() => GameMap::decoratedSurfaces()
- GameMap_GlowingSurfaces()   => GameMap::glowingSurfaces()
- GameMap_ScrollingSurfaces() => GameMap::scrollingSurfaces()

Removed the now redundant R_SurfaceList* family of functions.