matlab: fix plot functions for multi frequency far field data
matlab: fix missing filenames in CurvePort

Signed-off-by: Thorsten Liebig <Thorsten.Liebig@gmx.de>
octave: fix in h5readattr for ancient hdf5 shipped with Octave 3.6.x

Signed-off-by: Thorsten Liebig <Thorsten.Liebig@gmx.de>