Instanciation of net. Differents kind of nets are listed below :
SignalIn
: Creation of an input port
SignalOut
: Creation of an output port
SignalInOut
: Creation of an inout port
SignalUnknown
: Creation of an input/output port which direction is not defined
TriState
: Creation of a tristate port
CkIn
: Creation of a clock port
VddIn
: Creation of the vdd alimentation
VssIn
: Creation of the vss alimentation
Signal
: Creation of an internal net