VariantCollection memory leak

[jbromberg]

There seems to be a memory leak every time a VariantCollection is created. I've tested this with various other properties that return a VariantCollection and the issue is there for all of them. The function below showcases the problem in a rather extreme way.

    func memoryLeak() {
        let node = Node3D()

        for _ in 0...10000 {
            node.getPropertyList()
        }
    }

[migueldeicaza]

This is fixed, can you take it for a spin?