+ use IO_WRITE_FIELD for several fields (chosen form testcase 011_KW78CHEM)

 + use IO_WRITE_FIELD for several fields (chosen form testcase 009_ICARTT)

* added IO_WRITE_FIELD_BYNAME_X4 and IO_WRITE_FIELD_BYFIELD_X4 subroutines
  to IO_WRITE_FIELD procedure
* added IO_WRITE_FIELD_LFI_X4 subroutine to IO_WRITE_FIELD_LFI procedure
* added IO_WRITE_FIELD_NC4_X4 subroutine to IO_WRITE_FIELD_NC4 procedure

Philippe 30/03/2017: IO: use file structure instead of filename in arguments + add fields in TFIELDLIST

Philippe 27/03/2017: IO: use IO_WRITE_FIELD for FREE_ATM_PROFILE + propagate file structure to this subroutine

* added IO_WRITE_FIELD_BYNAME_X5 and IO_WRITE_FIELD_BYFIELD_X5 subroutines
  to IO_WRITE_FIELD procedure
* added IO_WRITE_FIELD_LFI_X5 subroutine to IO_WRITE_FIELD_LFI procedure
* added IO_WRITE_FIELD_NC4_X5 subroutine to IO_WRITE_FIELD_NC4 procedure

* added IO_WRITE_FIELD_BYNAME_C1 and IO_WRITE_FIELD_BYFIELD_C1 subroutines
  to IO_WRITE_FIELD procedure
* added IO_WRITE_FIELD_NC4_C1 subroutine to IO_WRITE_FIELD_NC4 procedure

+ use IO_WRITE_FIELD for several fields written in diachronic files

* several errors and problems corrected in mode_field.f90
* moved INI_FIELD_LIST call earlier in init_mnh.f90
* IO now works for: DIAG, PREP_IDEAL_CASE, PREP_NEST_PGD, PREP_PGD,
  PREP_REAL_CASE and SPAWNING

* added IO_WRITE_FIELD_BYNAME_L1 and IO_WRITE_FIELD_BYFIELD_L1 subroutines
  to IO_WRITE_FIELD procedure
* added IO_WRITE_FIELD_BYNAME_N1 and IO_WRITE_FIELD_BYFIELD_N1 subroutines
  to IO_WRITE_FIELD procedure
* added IO_WRITE_FIELD_LFI_N1 subroutine to IO_WRITE_FIELD_LFI procedure
* added IO_WRITE_FIELD_NC4_N1 subroutine to IO_WRITE_FIELD_NC1 procedure

                         and PRINT_MSG
                         Some calls are not yet (fully) ported

* added fields of MODD_GR_FIELD_n to TFIELDLIST
* adapted MNHWRITE_ZS_DUMMY_n and WRITE_DUMMY_GR_FIELD_n subroutines

* added several LB fields to TFIELDLIST
* added several fields to TFIELDLIST
* added scalar integer fields to TFIELDLIST and possibility to write them
* corrected several problems in TFIELDLIST
* added ALLOC_FIELD_SCALARS subroutine
* modified arguments of WRITE_LB_n

* added IO_WRITE_FIELD_LB interface
* added IO_WRITE_FIELD_BYNAME_LB and IO_WRITE_FIELD_BYFIELD_LB subroutines
  to IO_WRITE_FIELD_LB interface

* added IO_WRITE_FIELD_BYNAME_N2 and IO_WRITE_FIELD_BYFIELD_N2 subroutines
  to IO_WRITE_FIELD procedure
* added IO_WRITE_FIELD_LFI_N2 subroutine to IO_WRITE_FIELD_LFI procedure
* added IO_WRITE_FIELD_NC4_N2 subroutine to IO_WRITE_FIELD_NC4 procedure
* possible to write 2D integer values in output files

* added IO_WRITE_FIELD_BYNAME_T0 and IO_WRITE_FIELD_BYFIELD_T0 subroutines
  to IO_WRITE_FIELD procedure
* added IO_WRITE_FIELD_LFI_T0 subroutine to IO_WRITE_FIELD_LFI procedure
* added IO_WRITE_FIELD_NC4_T0 subroutine to IO_WRITE_FIELD_NC4 procedure
* added HCALENDAR optional argument to IO_WRITE_FIELD_ATTR_NC4

* modd_gridn.f90: all fields are now managed with TFIELDLIST
* added INI_FIELD_SCALARS subroutine
* corrected bugs for use of TFIELDLIST with all the PROGRAMS