Philippe 01/02/2022: OpenACC: use MNH_ALLOCATE_FLAT and MNH_RELEASE_FLAT instead of old allocate/release procedures

Juan 19/05/2021: add loop independent collapse , for all do conccurent & BR_ routine , or the do loop seq !!!

replace allocatable -> pointer,contiguous ;
allocate -> MNH_ALLOCATE_ZT*D ;
Some ARRAY SYNTAXE , with implicit copy inrelevenant -> DO CONCURRENT

# Conflicts:
#	src/MNH/gradient_m.f90
#	src/MNH/gradient_u.f90
#	src/MNH/gradient_w.f90
#	src/MNH/prandtl.f90
#	src/MNH/turb.f90
#	src/MNH/turb_hor_dyn_corr.f90
#	src/MNH/turb_hor_sv_corr.f90
#	src/MNH/turb_hor_thermo_corr.f90
#	src/MNH/turb_hor_uv.f90
#	src/MNH/turb_hor_uw.f90
#	src/MNH/turb_hor_vw.f90
#	src/MNH/turb_ver_dyn_flux.f90
#	src/MNH/turb_ver_thermo_flux.f90

# Conflicts:
#	src/MNH/advection_uvw.f90
#	src/MNH/advection_uvw_cen.f90
#	src/MNH/advecuvw_4th.f90
#	src/MNH/advecuvw_weno_k.f90
#	src/MNH/dyn_sources.f90
#	src/MNH/gradient_m.f90
#	src/MNH/gradient_u.f90
#	src/MNH/gradient_v.f90
#	src/MNH/gradient_w.f90
#	src/MNH/gravity.f90
#	src/MNH/mode_prandtl.f90
#	src/MNH/ppm.f90
#	src/MNH/prandtl.f90
#	src/MNH/resolved_cloud.f90
#	src/MNH/rmc01.f90
#	src/MNH/shuman.f90
#	src/MNH/tke_eps_sources.f90
#	src/MNH/tridiag_thermo.f90
#	src/MNH/tridiag_w.f90
#	src/MNH/turb.f90
#	src/MNH/turb_hor.f90
#	src/MNH/turb_hor_dyn_corr.f90
#	src/MNH/turb_hor_splt.f90
#	src/MNH/turb_hor_sv_corr.f90
#	src/MNH/turb_hor_thermo_corr.f90
#	src/MNH/turb_hor_thermo_flux.f90
#	src/MNH/turb_hor_tke.f90
#	src/MNH/turb_hor_uw.f90
#	src/MNH/turb_hor_vw.f90
#	src/MNH/turb_ver_dyn_flux.f90
#	src/MNH/turb_ver_sv_corr.f90
#	src/MNH/turb_ver_sv_flux.f90
#	src/MNH/turb_ver_thermo_corr.f90
#	src/MNH/turb_ver_thermo_flux.f90

Philippe 21/11/2019: give dimensions (:,...) when doing computations on arrays (better performance with PGI + remove some strange compiler messages)

Philippe 21/11/2019: automatic arrays -> allocatable (to work around PGI OpenACC bug) for turbulence+some others

Philippe 23/10/2019: OpenACC: rename _OPENACC key to MNH_OPENACC (_OPENACC is a standard OpenACC macro)

Philippe 03/10/2019: OpenACC: replace 'declare present' by 'data present' directives for assumed-size dummy arrays (to be standard compliant)

Philippe 02/10/2019: OpenACC: remove declare present directives from module declaration sections (to be standard compliant)