Replace some boost with std.

It doesn't help much, but we should still stop using those boost
facilities that are now standard.

NewKernel_d/include/CGAL/NewKernel_d/Cartesian_LA_functors.h

@@ -28,6 +28,7 @@
 #include <CGAL/transforming_iterator.h>
 #include <CGAL/NewKernel_d/store_kernel.h>
 #include <CGAL/Dimension.h>
+#include <type_traits>
 
 namespace CGAL {
 namespace CartesianDVectorBase {
@@ -66,64 +67,64 @@ template<class R_,class Zero_> struct Construct_LA_vector
 	}
 	template<class...U>
 	typename std::enable_if<Constructible_from_each<RT,U...>::value &&
-		boost::is_same<Dimension_tag<sizeof...(U)>, Dimension>::value,
+		std::is_same<Dimension_tag<sizeof...(U)>, Dimension>::value,
 	  result_type>::type
 	operator()(U&&...u)const{
 		return typename Constructor::Values()(std::forward<U>(u)...);
 	}
 	//template<class...U,class=typename std::enable_if<Constructible_from_each<RT,U...>::value>::type,class=typename std::enable_if<(sizeof...(U)==static_dim+1)>::type,class=void>
 	template<class...U>
 	typename std::enable_if<Constructible_from_each<RT,U...>::value &&
-		boost::is_same<Dimension_tag<sizeof...(U)-1>, Dimension>::value,
+		std::is_same<Dimension_tag<sizeof...(U)-1>, Dimension>::value,
 	  result_type>::type
 	operator()(U&&...u)const{
 		return Apply_to_last_then_rest()(typename Constructor::Values_divide(),std::forward<U>(u)...);
 	}
 	template<class Iter> inline
-	  typename boost::enable_if<is_iterator_type<Iter,std::forward_iterator_tag>,result_type>::type operator()
+	  typename std::enable_if_t<is_iterator_type<Iter,std::forward_iterator_tag>::value,result_type> operator()
 		(Iter f,Iter g,Cartesian_tag t)const
 	{
 		return this->operator()((int)std::distance(f,g),f,g,t);
 	}
 	template<class Iter> inline
-	  typename boost::enable_if<is_iterator_type<Iter,std::forward_iterator_tag>,result_type>::type operator()
+	  typename std::enable_if_t<is_iterator_type<Iter,std::forward_iterator_tag>::value,result_type> operator()
 		(int d,Iter f,Iter g,Cartesian_tag)const
 	{
 		CGAL_assertion(d==std::distance(f,g));
 		CGAL_assertion(check_dimension_eq(d,this->kernel().dimension()));
 		return typename Constructor::Iterator()(d,f,g);
 	}
 	template<class Iter> inline
-	  typename boost::enable_if<is_iterator_type<Iter,std::bidirectional_iterator_tag>,result_type>::type operator()
+	  typename std::enable_if_t<is_iterator_type<Iter,std::bidirectional_iterator_tag>::value,result_type> operator()
 		(Iter f,Iter g,Homogeneous_tag)const
 	{
 		--g;
 		return this->operator()((int)std::distance(f,g),f,g,*g);
 	}
 	template<class Iter> inline
-	  typename boost::enable_if<is_iterator_type<Iter,std::bidirectional_iterator_tag>,result_type>::type operator()
+	  typename std::enable_if_t<is_iterator_type<Iter,std::bidirectional_iterator_tag>::value,result_type> operator()
 		(int d,Iter f,Iter g,Homogeneous_tag)const
 	{
 		--g;
 		return this->operator()(d,f,g,*g);
 	}
 	template<class Iter> inline
-	  typename boost::enable_if<is_iterator_type<Iter,std::forward_iterator_tag>,result_type>::type operator()
+	  typename std::enable_if_t<is_iterator_type<Iter,std::forward_iterator_tag>::value,result_type> operator()
 		(Iter f,Iter g)const
 	{
 	  // Shouldn't it try comparing dist(f,g) to the dimension if it is known?
 		return this->operator()(f,g,typename R::Rep_tag());
 	}
 	template<class Iter> inline
-	  typename boost::enable_if<is_iterator_type<Iter,std::forward_iterator_tag>,result_type>::type operator()
+	  typename std::enable_if_t<is_iterator_type<Iter,std::forward_iterator_tag>::value,result_type> operator()
 		(int d,Iter f,Iter g)const
 	{
 		return this->operator()(d,f,g,typename R::Rep_tag());
 	}
 
 	// Last homogeneous coordinate given separately
 	template<class Iter,class NT> inline
-	  typename boost::enable_if<is_iterator_type<Iter,std::forward_iterator_tag>,result_type>::type operator()
+	  typename std::enable_if_t<is_iterator_type<Iter,std::forward_iterator_tag>::value,result_type> operator()
 		(int d,Iter f,Iter g,NT const&l)const
 	{
 		CGAL_assertion(d==std::distance(f,g));
@@ -132,7 +133,7 @@ template<class R_,class Zero_> struct Construct_LA_vector
 		return typename Constructor::Iterator()(d,CGAL::make_transforming_iterator(f,Divide<FT,NT>(l)),CGAL::make_transforming_iterator(g,Divide<FT,NT>(l)));
 	}
 	template<class Iter,class NT> inline
-	  typename boost::enable_if<is_iterator_type<Iter,std::forward_iterator_tag>,result_type>::type operator()
+	  typename std::enable_if_t<is_iterator_type<Iter,std::forward_iterator_tag>::value,result_type> operator()
 		(Iter f,Iter g,NT const&l)const
 	{
 		return this->operator()((int)std::distance(f,g),f,g,l);