Remove workarounds for CGAL < 3.6

src/graph/generation/graph_triangulation.cc

@@ -47,8 +47,6 @@ bool operator==(const SimpleTriangulation::Vertex& a,
 }
 }
 
-// periodic triangulation is only available in more recent versions of CGAL
-#if (CGAL_VERSION_NR >= 1030500000)
 #include <CGAL/Periodic_3_Delaunay_triangulation_traits_3.h>
 #include <CGAL/Periodic_3_Delaunay_triangulation_3.h>
 typedef CGAL::Periodic_3_Delaunay_triangulation_traits_3<Kernel> GT;
@@ -63,7 +61,6 @@ bool operator==(const PeriodicDelaunayTriangulation::Vertex& a,
     return a.point() == b.point();
 }
 }
-#endif
 
 // comparison missing in 4.13
 #if (CGAL_VERSION_NR >= 1041301000)
@@ -107,14 +104,8 @@ void triangulation(GraphInterface& gi, boost::python::object points,
         }
         else
         {
-#if (CGAL_VERSION_NR >= 1030500000)
             get_triangulation<PeriodicDelaunayTriangulation, std::true_type>()
                 (g, points_array, pos_map);
-#else
-            throw ValueException("Periodic Delaunay triangulation is only "
-                                 "available with versions of CGAL newer than "
-                                 "3.5.0.");
-#endif
         }
     }
 }