Release Notes:
- Improved: FPSRigidBodyWalker values are now saved.
- Fixed: Look rotation now matches spawnpoint direction when changing scenes.
- Added: SceneFaderCanvas for use with SceneTransitionManager.
- Improved: Added SaveSystem methods LoadAdditiveScene, UnloadAdditiveScene.
- Improved: Savers can now implement optional ApplyDataImmediate and OnRestartGame methods.
- Fixed: Moved DiskSavedGameDataStorer initialization code from Start to Awake so other scripts can check for saved games in their own Start methods.