Philippe 09/12/2016: re-added #ifndef MNH_SP4 to prevent problems when compiling on Blue Gene/Q with -qautodbl=4

Merge branch 'MNH-53-branch' of mesonh2.aero.obs-mip.fr:/gitrepos/MNH-git_open_source-lfs into MNH-53-branch

(cherry picked from commit b5702ae3)

(cherry picked from commit 9746cd3e)

(cherry picked from commit 7a1e8bc2)

Revert "Christine 25/11/2016 : Correction on the flag for Strang splitting to insure reproducibility between START and RESTA"

This reverts commit d4b7d37a.

Merge branch 'MNH-53-branch' of mesonh2.aero.obs-mip.fr:/gitrepos/MNH-git_open_source-lfs into MNH-53-branch
gaelle 25/11/2016

Christine 25/11/2016 : Correction on the flag for Strang splitting to insure reproducibility between START and RESTA

(cherry picked from commit 532f44d0)

(cherry picked from commit c3ec51f7)

Philippe 24/112016: lfi2cdf: bug correction: size of buffer was too small when doing cdf2lfi (length of comment was not taken into account)

Philippe 24/11/2016: lfi2cdf: nc4 files have again a .nc4 extension to be consistent with MESONH and the scripts

Conflicts:
	src/MNH/advec_ppm_algo.f90
	src/MNH/advection_metsv.f90
	src/MNH/modeln.f90
	src/MNH/ppm_met.f90
	src/MNH/ppm_scalar.f90

(cherry picked from commit e387e7c8)