* 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