[code] Get maximum speed in ways

[Yona-TYT]

This is in order to know if a way is passable or not, for example rivers that have speed "0" are not passable. 

[Dwachs]

This will give the max speed of the way including the speed limits of crossings, way objects, city roads etc. If you want the speed limit of the way the you can use way.get_desc().get_topspeed()

[Yona-TYT]

This will give the max speed of the way including the speed limits of crossings, way objects, city roads etc. If you want the speed limit of the way the you can use way.get_desc().get_topspeed()

This can also be very useful, since it is more generalized