(Routing implementation in bug 698470)

One visual issue that becomes apparent when adding routes is that the bubbles for starting point and end point overlap the route (or the other way round).

Possible solution: Make MapLocation smarter about the bubble positioning. If we had four variations of the bubble with the arrows pointing to the four cardinal directions we could almost always pick one that does not overlap with the route. A fast and easy implementation would just look at the overlap between the bounding boxes of the bubble and the route.

A more general solution would avoid the various bubbles from overlapping each other as well, but I believe the route avoidance is more important as that cannot be solved by just zooming in closer.