(LTIMEDEP is only set for some test variables)

* set JPXKRK to NLFIMAXCOMMENTLENGTH
* add NSTRINGCHUNKSIZE parameter in mode_netcdf (instead of IMULT)
* typo

Philippe 22/03/2018: IO: use CFORMAT field of TFILEDATA instead of relying on LIOCDF4, LLFIOUT and LLFIREAD
This prevents some problems when mixing LFI and netCDF files (ie in cdf2lfi)
+ cleaning use of modd_io_ll for LIOCDF4, LLFIOUT and LLFIREAD (and others)

* improvements
* split option works again

Philippe 19/03/2018: IO: Z-split files: pass also the optional HFORMAT argument (necessary for LFI2CDF)

Philippe 16/03/2018: lfi2cdf: remove file suffix from hinfile and houtfile to manage more cleanly filenames

Philippe 13/02/2018: IO_GUESS_DIMIDS_NC4: manage variables with CLBTYPE/=NONE + add a return value + problems are now WARNING instead of FATAL

* write NF90_INT1 instead of NF90_INT for logicals
* use IO_WRITE_FIELD (not yet done everywhere)
* if NTYPE is unknown => fatal error
* do not try to read JPVEXT (never written)

Philippe 09/03/2018: lfi2cdf: remove redundant fields of workfield (present also in TFIELDDATA) + remove read_data_lfi