Read JSON data from Python/Fortran

[edigiacomo]

It would be useful to read a JSON file from Python:

importer = dballe.Importer("JSON")
with importer.from_file("test.json") as f:
    for msg in f:
        print("{m.report},{m.coords},{m.ident},{m.datetime},{m.type}".format(m=msg))

[spanezz]

It should work now, after the fix of #202

[edigiacomo]

I confirm that it works (with a little delay 😬 )