added test for setting individual vehicle length via TraCI

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@15211 29f149b2-0c63-11e1-8f5c-a347f6a9acd0
fixing signed / unsigned bug

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@15212 29f149b2-0c63-11e1-8f5c-a347f6a9acd0
fixing warnings refs #12

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@15213 29f149b2-0c63-11e1-8f5c-a347f6a9acd0
adding quartiles to stats

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@15214 29f149b2-0c63-11e1-8f5c-a347f6a9acd0