updated the sgf reader regarding segment creation:   sgf format is single segment only - now a segment is created,   and per default all cells are added to this segment (id: 0)
updated the sgf reader regarding segment creation:
  sgf format is single segment only - now a segment is created,
  and per default all cells are added to this segment (id: 0)

viennagrid/viennagrid-dev,viennagrid/viennagrid-dev,viennagrid/viennagrid-dev