waveguide loss, frequency.t, shorthand media properties.

ADD: RectangularWaveguide loss,  need to add test.
ADD: data.materials dict to hold common material parameters
	in a nested dict. could serialize this and read it in as well.
	would be nice to get a recognised source for this.
ADD: Frequency.t property thats correct
ADD: media.gamma media.portz0 media.Z0 for shorthand
	reference to frequenctly used properties

CHG: save_all_figs, fixed a bug. i hate that function.