Allow Materializer (and Proxy, I guess) output slot to be considered part of network

[GreyMario]

Issue type:

• :heavy_plus_sign: Feature request

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Short description:

Allow Variable Cards found in the output slot of a Materializer (and Proxy, being a similar block) to be considered as part of the network for the purposes of calculations.

This enables a user to, for example, recycle a card through the Materializer to lock a tracked value at a specific point in time, and use the value in calculations without needing to place the output card into a Variable Store.

[rubensworks]

Thanks for the suggestion!