support for Lorentz dispersive material parameter

Signed-off-by: Thorsten Liebig <Thorsten.Liebig@gmx.de>
fixes in Lorentz material property

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

Signed-off-by: Thorsten Liebig <Thorsten.Liebig@gmx.de>
fix copy/paste error in export_gerber

Signed-off-by: Thorsten Liebig <Thorsten.Liebig@gmx.de>
matlab: new functions to calculate Lorentz and Debye material properties

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