Added some functions:
* to get the pose at a given distance in the link. * to get the curvature at a given distance in the link. * to get the closest node, node index, lane, lane index, segment, segment index and pose to a given point. * to get the number of lane objects and a reference to them. * to udpate the index of lanes and nodes when creating new roads. * to update the node index from a path.