Fix Sponges

[SpaceManiac]

The physics revamp is complete except for sponges, which perform erratically if at all.

One way could be to have sponges work in three parts:

1. Cancel out any physics tasks that will create fluids inside their radius
2. Remove any fluids inside their radius (by nature of an Air physics task)
3. Create placeholder Air physics tasks in any air inside their radius that water and lava will not expand into

[AtkinsSJ]

Sounds pretty solid. I was thinking you could create a SolidAir block which would prevent the liquid spreading, but then you'd still need to check proximity to sponges... Might still be slightly more efficient.

[SpaceManiac]

Alright, implemented and working!