Replace the custom shape with unidentified shape in the GeoModelTree
This merge request from @boudreau :
- replaces the custom shape with an unidentified shape in the GeoModelTree
- Geo2G4 code is revised coherently and code is arranged for LArGeoModel to store GeoUnidentifiedShape rather than LArCustomShape
- dump-geo writes out GeoUnidentifiedShape properly
This changes are compatible with the new EMEC variants (Wheel,Cone,Slices) and have been tested in standalone way through FullSimLight.