Philippe 29/01/2019: SURFEX: bug corrections + missing zero-size allocations (detected with NAG compiler)

Quentin 24/01/2019: minor correction on XCEDIS : cancellation of previous modification of XCEDIS with respect to the mixing length

Quentin 23/01/2019: modification of initialization of PM09 convection scheme at hectometric scale.The mass-flux at the surface is reduced and converge to EDKF value when resolution is meso-scale. Flag to turn on : LGZ = TRUE by default. Modifs by Rachel Honnert

Philippe 22/01/2019: replace double precision declarations by real(kind(0.0d0)) (to allow compilation by NAG compiler)

Gaelle 22/01/2019: add ARPEGE and AROME GRIB 2 (IMODEL=6 and IMODEL=7 in read_all_data_grib_case.F90) and adaptation to EPYGRAM tool

Philippe 21/01/2019: add LIO_ALLOW_NO_BACKUP and LIO_NO_WRITE to modd_io_ll to allow to disable writes (for bench purposes)

Quentin 17/01/2019: cleaning : remove of cyclic conditions-like on DP and ZA variables (useless here)

Philippe 11/01/2019: NVERB_INFO->NVERB_WARNING for zero-size fields + ignore them for LFI files (already done for nc4)

+ some corrections in the error messages

+ move IOFREEFLU and IONEWFLU to mode_io_file_lfi.f90
+ move management of NNCID and NLFIFLU to the nc4 and lfi subroutines

Quentin 10/01/2019: add a local filtering for very high slopes in PGD step (for a better chance of pressure solver convergence). In namelist NAM_ZSFILTER : possibility to activate or not (LHSLOP), choose the number of filtering iterations (NLOCZSFILTER) and the slope value (XHSLOP= Dz/Dx and Dz/Dy) where the filter is applied