Problem when using speed limit estimation and turn restrictions

[karussell]

Complex turn costs introduce artificial edges and copy the flags. But they won't copy external datastructures like we use for MaxSpeedCalculator (because we don't want to store it long-term, just for the import). But then the max_speed is not infinity but 0 leading to "max_speed cannot be <=0 but was 0.0" for these artificial edges.