Land identification [old issue from BitBucket]
Created by: jdha
To be checked: There appears to be a bug when there is only one grid point of land in the outer halo and water in neighbouring cells (e.g. bdy_msk(:,0)=0 and say bdy_msk(10:20,1)=1).Pynemo treats bdy_msk(10:20,1) as an open boundary, when in fact it isn't ....