Philippe 13/06/2017: IO: bug corrections

* IO_WRITE_FIELD_LFI_C0: do not trim character string (size must be the same at read)
* IO_WRITE_FIELD_LFI_T0: use TZFIELD instead of TPFIELD
* IO_WRITE_HEADER: write DAD_NAME with a correct length string (for LFI files)
* NCREADN0, NCREADN1 and NCREADN2: accept NF90_INT1 used when writing booleans