walkingarea width now takes into account the width of connected sidewalks

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@17435 29f149b2-0c63-11e1-8f5c-a347f6a9acd0
added coordinate transformation to PositionVector interface

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@17436 29f149b2-0c63-11e1-8f5c-a347f6a9acd0