Direction ids by route_master members

[gammapopolam]

It is assumed that route_master relation possibly has only two members: forward and back trips. But in some cases there are more than two participants, as there are shortened routes in one or both directions.

Don't really know how to handle these cases so the direction ids could be not acceptable:

A->B: 0
B->A: 1
A->C: 1
C->A: 0

But in fact it should be like this:

A->B: 0
B->A: 1
A->C: 0
C->A: 1