Integrated the new layer height spans with configs into the backend.

Fixed some compiler warnings.

xs/xsp/Print.xsp

@@ -100,7 +100,6 @@ _constant()
         %code%{ RETVAL = const_cast<PrintObjectPtrs*>(&THIS->objects()); %};
     Ref<PrintObject> get_object(int idx)
         %code%{ RETVAL = THIS->objects()[idx]; %};
-    void reload_object(int idx);
     size_t object_count()
         %code%{ RETVAL = THIS->objects().size(); %};
 
@@ -141,7 +140,6 @@ _constant()
             }
         %};
         
-    void add_model_object(ModelObject* model_object, int idx = -1);
     bool apply_config_perl_tests_only(DynamicPrintConfig* config)
         %code%{ RETVAL = THIS->apply_config_perl_tests_only(*config); %};
     bool has_infinite_skirt();