Proxies should preserve properties during expander restart

[JensOgorek]

Since Proxies & expanders can handle restarts, they should also preserve their last property state.

[JensOgorek]

An extra effect of this: When we load a startup script, that has some properties settings like a.inverted = true (for Input), it will get lost.
The expander is not ready at the time the expression gets executed.
Since it needs like 2.5 seconds to be ready and the script is executed imminently.

This is not a separate Issue and will be resolved with this as well.