Convert write_string to use the scalar interface.
Convert write_string to use the scalar interface.

Much simpler than converting to an array and using the variable length approach (as found
in all offical HDF5 examples).

hande-qmc/hande,ruthfranklin/hande,hande-qmc/hande,hande-qmc/hande,hande-qmc/hande,hande-qmc/hande