randomTrips (and sumolib) can now handle vClass permissions fix #798

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@15768 29f149b2-0c63-11e1-8f5c-a347f6a9acd0
randomTrips no longer start end the outgoing fringe nor end at the incoming fringe. The efficiency of finding edges was increased by using separate source/sink generators

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@15769 29f149b2-0c63-11e1-8f5c-a347f6a9acd0