make land initial condition into boundary condition?

[amoodie]

Would it be acceptable to have all the land pixels increase by SLR each timestep? I.e., this would maintain the initial condition of the land cells as a boundary condition for the whole run.

Something like the below in finalize_timestep, where SLR is computed:

self.eta[self.cell_type == -2] += SLR

Needs to be verified that this works/makes sense. Purpose of this is mostly for DeltaMetrics, where the boundary condition would help ensure proper masking, but it makes results in pyDeltaRCM make more sense too, when there is significant SLR.

• this should be a non-breaking change, because the land pixels don't have any water/sediment routing effect anyway