* New: In Anabatic::NetBuilder, set all the attributes as private and
create accessors and mutators.
Finish virtualising all GCell build methods and transfer them
into the NetBuilderHV class.
Build methods now return a boolean to tell if the GCell was
processed or not, to allow cascading in the "big switch".
Reorganise the "big switch" in separate sections only partially
cascading.
Truly fuse the *big switch* for channel routing and over-the-cells.
Create a new method "_do_globalSegment()" to delagate the
drawing of global segments between two GCell to the derived classes.
* New: In Anabatic, rename GCellTopology to NetBuilder, expose the class
(no longer in a local namespace).
NetBuilder become a base class performing the walkthrough the Net
tree. Derived class are tasked to build routing for specific gauge.
NetBuilderHV is created to manage all gauge with metal2 horizontal
and metal3 vertical.
In our terminolgy we consider that the first routing metal is
metal2. Metal1 is used inside the standard cells.
Jean-Paul Chaput