small refactorings to avoid too much int casting, refs #12

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@16616 29f149b2-0c63-11e1-8f5c-a347f6a9acd0
traci e2 tests are now correct, refs #1171, #21

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@16617 29f149b2-0c63-11e1-8f5c-a347f6a9acd0