Preset scene settings from GH

[mnaugle-tt]

It would be great to be able to predetermine scene settings from GH.

One option would be to add optional inputs onto the various components to do this, or have a specific 'scene settings' component.

Things I'd like to be able to control:
-Setting individual layers to automatically be visible or invisible upon loading
-The ambient and point light colors
-The background color of the scene
-The initial view that is loaded per issue #13