bug in MLD calculation

[ggalli00]

bit.sea/src/bitsea/validation/deliverables/metrics.py

Line 33 in fd462b7

def MLD(Temperature, Salinity, Pres):

Computes conservative from in situ temperature, but then does not use it to find mld depth.

[gbolzon]

@lfeudale, I've just verified that MLD() is never called, there are no calls in bit.sea, ogstm_preproc or ogstm_postproc

Is there a good reason to keep it?
It returns also DENSITY and POTENTIAL DENSITY at mld That's why it computes conservative temperature.
Is it worth to keep them?
Maybe it's better to have explicit an function for density?

[ggalli00]

@gbolzon, one reason to keep MLD() is that we will need it for new BBP700 to POC conversion that we plan to implement. No need to also have density and potential density at MLD, but doesn't hurt either.