Develop testeleftheria

Hi,

I added a new function (vertmeanvar) to compute weighted vertical means in the ocean, on either temperature or salinity (potentially on every quantity on gridT). The input levels should be in level number, and they are specified in the configure file with the 2 new variables level1 and level2 (the modified config file is part of the commit). People who would be interested in this and could check it: @vguemas  @cprodhomme  @pabretonniere

Cheers
Eleftheria

Develop ice extraction issue

Solves issue #3 , opened by @fmassonnet

add siasiesiv to the list of postprocessing that need the extraction of ice files from the tar file.

Develop testeleftheria

The bug of usalc is fixed here.

This test is not suitable anymore since the naming convention has changed in diags to be the same as MMO

if several members, oce will exist for previous members whereas sstsssmld rather for the followings so that lstfiles can be empty

if only one chunk, cdo mergetime is not useful and it would not work because the input and output files would have the same name

oce needs to be before sstsssmld so that oce is not already in the workdir when sstsssmld is treated