[Patch, libfortran] Reduce default precision for list-directed and G0 real output

[Dominique Dhumieres]

Janne,

Please don't rush to commit such a patch.
IMO the outputs for default format have already changed too often
for my taste and if changed again it should discussed more seriously.

Cheers,

Dominique

PS I'll be out of town without net access for the newt two days.