Fillers: Removal of old FillRectilinear, using of "override" instead

of "virtual" where applicable.

src/libslic3r/Fill/FillBase.cpp

@@ -34,7 +34,6 @@ Fill* Fill::new_from_type(const InfillPattern type)
     case ipTriangles:           return new FillTriangles();
     case ipStars:               return new FillStars();
     case ipCubic:               return new FillCubic();
-//  case ipGrid:                return new FillGrid();
     case ipArchimedeanChords:   return new FillArchimedeanChords();
     case ipHilbertCurve:        return new FillHilbertCurve();
     case ipOctagramSpiral:      return new FillOctagramSpiral();