Let sponges survive in "moist" storeboxes

When sponges are placed in storeboxes that are themselves considered moist, such as the water-filled ceramic pot from wc_pottery, they die regardless. While this does not affect Vanilla NodeCore itself, since it does not have such a storebox itself, it would make logical sense for this to work. So this patch will make the sealed_or_notdry function that living sponges use to decide if they should die return true if stored in a node that's in the moist group.

Here's a picture of living sponges surviving in the aforementioned waterpots with this patch:

Alternatively, these functions could be exposed so they could be overridden by other mods, such as wc_pottery. This might be preferred with or without the patch, since it would allow other mods that add additional sea-life to make use of the same logic without copying the code whole (something wc_sealife could benefit from), and a mod like wc_pottery could patch the functionality in by overriding the function.

Let me know what you think. I could work on such a change as well and submit a merge request.