Removed _change_notify

-For inspector refresh, the inspector now detects if a property change by polling a few times per second and then does update the control if so. This process is very cheap.
-For property list refresh, a new signal (property_list_changed) was added to Object. _change_notify() is replaced by notify_property_list_changed()
-Changed all objects using the old method to the signal, or just deleted the calls to _change_notify(<property>) since they are unnecesary now.

scene/gui/link_button.cpp

@@ -231,7 +231,7 @@ bool LinkButton::_set(const StringName &p_name, const Variant &p_value) {
 				update();
 			}
 		}
-		_change_notify();
+		notify_property_list_changed();
 		return true;
 	}