* New: In Hurricane::Diagonal, new object to represent 45° and 135°
segments (X routing). Althought they have source & target, they
are not articulated like Horizontal & Vertical, due to the
combined displacement of X and Y (diagonal).
Maybe we should create a common class for all the polygons
to make "::getContour()" a method.
Now we could represent self capacitances and high frequency
wires.