Twisted pair cable over ground plane test case.

Two models are genereated here, the first using FastHenry and the second
using the original SACAMOS model with L and C matrices calculated using the
Laplace solver.

FD_TWISTED_PAIR_OVER_GROUND_PLANE_FASTHENRY
FD_TWISTED_PAIR_OVER_GROUND_PLANE_LAPLACE

A comparison of the results of the models can be plotted with the command

gnuplot plot_comparison.plt