Per a conversation here:
https://content.minetest.net/threads/4470/
This ensured builtin_item loads first and then wielded_light can affect the torches
properly. Without this, held torches may illuminate, but dropped torches will not.
Fixed light flicking.
Make it a little more extensability.
Make floodable items not emitting light underwater.
Add Hades Revisited support for underwater light.