matlab: enable 'x', 'y' or 'z' as port direction char

Signed-off-by: Thorsten Liebig <Thorsten.Liebig@gmx.de>
matlab: waveguide port fix

Signed-off-by: Thorsten Liebig <Thorsten.Liebig@gmx.de>
matlab: new coaxial port and example

Signed-off-by: Thorsten Liebig <Thorsten.Liebig@gmx.de>
SAR: fix typo for SAR av. method

Signed-off-by: Thorsten Liebig <Thorsten.Liebig@gmx.de>
matlab: allow empty ports to be passed through

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