- Moved the background color from the Scene to the SceneWindow.  This seems more appropriate, especially in a multi-window environment where you want to potentially clear the "camera" view rather than clearing the Scene itself.
- Reverted the Canvas to default to clearing itself.
- The Sandbox now changes the Canvas color and not the SceneWindow.
- Updated the MultiWindowToy to show optionally rendering specific Scene Layers as well as mounting to an object using rotation.