fix routing graph construction and calculation of shortest route

[markomiz]

fixes the issue #77 :

#77

Changes:

• added operators == and != to lanekeys
• reimplemented get_routing_graph (using existing junction parsing)
• reimplemented shortest_path

[pageldev]

Looks good. Maybe @Novadgaf can confirm that this fixes his issue?

Also can you run some tests on the default data.xodr odrviewer.io uses? Ideally running your routing on some start/end combinations and checking if they are correct / as expected.

[markomiz]

@pageldev I've tested on many carla maps now and some other maps I have access to - it is working reliably now. One thing that could be improved in the future however is allowing lane changes to neighbouring lanes as part of the routing which isn't currently possible.