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/2d/path_2d.cpp

@@ -319,8 +319,6 @@ void PathFollow2D::set_offset(float p_offset) {
 
 		_update_transform();
 	}
-	_change_notify("offset");
-	_change_notify("unit_offset");
 }
 
 void PathFollow2D::set_h_offset(float p_h_offset) {