Get list of all SymbolInstances and create SceneNode based on a SymbolInstance

[pklaschka]

@rehdie

I assumed, that creating a symbol means: create a new symbol (adding a new symbol to the assets panel). Maybe that’s a misunderstanding…

I wasn’t too sure about that either, but

@drcwj

Currently it is only possible to duplicate existing symbols.

lets it sound to me as if it’s about creating a new instance …