* 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