fix #1366. (generated network was invalid)

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@17449 29f149b2-0c63-11e1-8f5c-a347f6a9acd0
fix #1361. Vehicles that ignore vClass and drive across walkingAreas may still cause collisions but the simulation does not crash

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@17450 29f149b2-0c63-11e1-8f5c-a347f6a9acd0