update to domain to better handle more cases with spatially varying dz
update to domain to better handle more cases with spatially varying dz

note, space varying dz is unstable because it isn't accounted for in the CFL criteria yet
also space varying dz is not accounted for in the linear wind solution

gutmann/icar,NCAR/icar,NCAR/icar,gutmann/icar,gutmann/icar,NCAR/icar