Virtual lysimeter

See merge request !7

Merge branch 'virtual_lysimeter' of https://gitlabext.wsl.ch/snow-models/snowpack into virtual_lysimeter

Added new parameter MS_SURFACE_RUNOFF, which is MS_SNOW if SWE > 0, and MS_RAIN - MS_EVAPORATION otherwise, i.e. the true mass flux through the soil surface all year long

In some cases (this happened with a very short dataset filled by data
generators), MeteoIO returns an empty data vector (in this case, when exhausting
its buffer). This was not tested for in Snowpack, leading to segfault (trying to
access a given station in the vector that is empty).

Bulk and brine salinity (0540, 0541) were written before 0535, in contrast with what was declared in the file header.

Correcting a typo, and testing explicitly for density option "FIXED" and throwing an error otherwise (i.e., not assuming that after evaluating the other options, everything else must be "FIXED").

Re-introducing: "Adding the possibility to suppress writing *.haz files (controlled by the key HAZ_WRITE in [Output] section)", which was overwritten with the previous commit. Note that CaaMLIO.h had inconsistent end-of-line characters.

This is necessary when the user selects SLOPE_FROM_SNO=false but does
not provide the slope information with the meteo forcings

Pipeline without manual zipping

See merge request !5