Add squared radius for a point to make kernels model of the alpha shape traits class

Kernel_23/include/CGAL/Kernel/global_functions_2.h

@@ -952,6 +952,14 @@ side_of_oriented_circle(const Point_2<K> &p,
   return CGALi::side_of_oriented_circle(p, q, r, t, K());
 }
 
+template < class K >
+inline
+typename K::FT
+squared_radius(const Point_2<K> &p)
+{
+  return CGALi::squared_radius(p, K());
+}
+
 template < class K >
 inline
 typename K::FT

Kernel_23/include/CGAL/Kernel/global_functions_3.h

@@ -991,6 +991,14 @@ squared_radius(const Point_3<K> &p, const Point_3<K> &q)
   return CGALi::squared_radius(p, q, K());
 }
 
+template < class K >
+inline
+typename K::FT
+squared_radius(const Point_3<K> &p)
+{
+  return CGALi::squared_radius(p, K());
+}
+
 template < class K >
 inline
 typename K::Vector_3

Kernel_23/include/CGAL/Kernel/global_functions_internal_2.h

@@ -826,6 +826,14 @@ side_of_oriented_circle(const typename K::Point_2 &p,
   return k.side_of_oriented_circle_2_object()(p, q, r, t);
 }
 
+template < class K >
+inline
+typename K::FT
+squared_radius(const typename K::Point_2 &p, const K &k)
+{
+  return k.compute_squared_radius_2_object()(p);
+}
+
 template < class K >
 inline
 typename K::FT

Kernel_23/include/CGAL/Kernel/global_functions_internal_3.h

@@ -779,6 +779,14 @@ squared_radius(const typename K::Point_3 &p,
   return k.compute_squared_radius_3_object()(p, q);
 }
 
+template < class K >
+inline
+typename K::FT
+squared_radius(const typename K::Point_3 &p, const K &k)
+{
+  return k.compute_squared_radius_3_object()(p);
+}
+
 template < class K >
 inline
 typename K::FT