Fixed name lookup problem for calls to serialize() on network objects.

dlib/dnn/core.h

@@ -597,6 +597,10 @@ namespace dlib
     template <typename LAYER_DETAILS, typename SUBNET, typename enabled = void>
     class add_layer;
 
+    template <typename LAYER_DETAILS, typename SUBNET, typename enabled>
+    void serialize(const add_layer<LAYER_DETAILS,SUBNET,enabled>& item, std::ostream& out);
+    template <typename LAYER_DETAILS, typename SUBNET, typename enabled>
+    void deserialize(add_layer<LAYER_DETAILS,SUBNET,enabled>& item, std::istream& in);
 
     template <typename T, typename U>
     struct is_nonloss_layer_type<add_layer<T,U>> : std::true_type {};
@@ -2154,6 +2158,11 @@ namespace dlib
         template < typename net_type, typename solver_type > friend class dnn_trainer; 
     };
 
+    template <typename LOSS_DETAILS, typename SUBNET>
+    void serialize(const add_loss_layer<LOSS_DETAILS,SUBNET>& item, std::ostream& out);
+    template <typename LOSS_DETAILS, typename SUBNET>
+    void deserialize(add_loss_layer<LOSS_DETAILS,SUBNET>& item, std::istream& in);
+
 // ----------------------------------------------------------------------------------------
 
     template <typename LOSS_DETAILS, typename SUBNET>