Remove unnecessary empty ctor deletion in bvh_node

Author: hollasch

books/RayTracingTheNextWeek.html

@@ -692,7 +692,6 @@
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
     class bvh_node : public hittable {
         public:
-            bvh_node() = delete;   // Disallow uninitialized BVH nodes
             bvh_node(hittable_list& list, double time0, double time1)
                 : bvh_node(list.objects, 0, 0, time0, time1)
             {}

src/TheNextWeek/bvh.h

@@ -18,8 +18,6 @@
 
 class bvh_node : public hittable  {
     public:
-        bvh_node() = delete;
-
         bvh_node::bvh_node(hittable_list& list, double time0, double time1)
             : bvh_node(list.objects, 0, list.objects.size(), time0, time1)
         {}

src/TheRestOfYourLife/bvh.h

@@ -18,8 +18,6 @@
 
 class bvh_node : public hittable  {
     public:
-        bvh_node() = delete;
-
         bvh_node::bvh_node(hittable_list &list, double time0, double time1)
             : bvh_node(list.objects, 0, 0, time0, time1)
         {}