add copy constructeur

Author: francoisbonneau

include/geode/stochastic/spatial/object_set.hpp

@@ -35,6 +35,8 @@ namespace geode
         ObjectSet() noexcept = default;
         ObjectSet( ObjectSet&& ) noexcept = default;
         ObjectSet& operator=( ObjectSet&& ) noexcept = default;
+        ObjectSet( const ObjectSet& ) noexcept = default;
+        ObjectSet& operator=( const ObjectSet& ) noexcept = default;
 
         const Type& get_object( index_t index ) const;