Nautilus controls and enhancements

Nautilus need to be able to vertically ascend and descend.

Also, it's hard to see the ocean floor when riding the nautilus close to it which causes the nautilus to get stuck on blocks sitting on the ocean floor. I suggest making it glide over blocks for a smooth underwater experience.

It needs to be able to be carried in a bucket so it'll be useful in explorations away from the homebase.