Fix inertial resistance

[Zac8668]

The current implementation has it's flaws, mainly this:

For now it kinda tells how hard it is to collapse to sand like, but it shouldn't form those types of "sand structures" at all.

[Zac8668]

To fix this we probably have to change the priority of velocity based movement or automata like movement of the atoms.
We should maybe remove the doubled gravity implementations too.