Mars GCM:
Add the new version of the MCS observer simulator program simu_MCS.F90, replacing the old version simu_MCS_temp.F90.
The program can now handle (ie, interpolate and bin like the MCS file) any 4D GCM variable, by linking them to
a MCS variable among temp (default), dust and water ice, serving as reference for the binning.
More details in the preface of simu_MCS.F90 and in simu_MCS.def