Answers change with ice model layout

[wfcooke]

I can get different answers if I change the ice model layout even with the same total core count. i.e use 144,2 vs 36,8. I think it has to do with the domain size getting too small and halo updates needing to reach across two domains to update.
A check on the domain size at initialization should mitigate this.

This may be related to issue #5 although I see this with the same core count.

I think b913118 may play in here. Stochastic perturbations in iceberg kinematics are grid dependent (unless I am mistaken).