* Change: In Anabatic:
- In Dijkstra, replace _toWires() by _trackback() which is called
immediatly on reaching a target.
- In Constants & GCell, added flags for typing the GCells. We now
have:
* DeviceGCell, for analogic devices.
* ChannelGCell, for resizable routing channels.
* StrutGCell, for fixed spaces in analog designs.
* MatrixGCell, for square tile in digital designs.