refactoring refs #12

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@16888 29f149b2-0c63-11e1-8f5c-a347f6a9acd0
refactoring to make method signatures consistent refs #12

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@16889 29f149b2-0c63-11e1-8f5c-a347f6a9acd0