Separating grid into ocean and atmosphere #107
Description
Right now, having a separate grid object from the ocean and atmosphere assumes that the grid is the same for the ocean and atmosphere and doesn't offer another option.
In the long run, if we don't want this to be true, we might want the ocean and atmosphere to each have their own grid fields, as the current grid is only used for coupling. This would allow for more flexibility and would mean that the user didn't have to build a grid, just the atmos and ocean objects.
If this is the case, you would also need to keep track of which floes are in which grid cells for two-way coupling (if that was your goal). At this point, I would suggest reexamining the CellFloes objects, as they are a little confusing and might make more sense somewhere else in the Model setup.