add a warning if select_rStar=2 with nonlinFreeSurf <> 4  (not consistent to account for the slope of the coordinate when  ignoring the variations of level-thickness in PhiHyd calculation)
add a warning if select_rStar=2 with nonlinFreeSurf <> 4
 (not consistent to account for the slope of the coordinate when
 ignoring the variations of level-thickness in PhiHyd calculation)

altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h