(cherry picked from commit b5702ae3)

Philippe 24/112016: lfi2cdf: bug correction: size of buffer was too small when doing cdf2lfi (length of comment was not taken into account)

Philippe 24/11/2016: lfi2cdf: nc4 files have again a .nc4 extension to be consistent with MESONH and the scripts

* return is not allowed in main program => stop
* number of variables to be read and written was not computed correctly
* name of the outputfile is now correct
* treat correctly the last variable given with -v option
* correct bugs if LOWMEM is set (variables with length=1, reading of TEXT variables)
* correct types when LFI_INT is 8