allowing different level 1 elements, refs #1138

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@15592 29f149b2-0c63-11e1-8f5c-a347f6a9acd0
adapting xml2csv tests, refs #1138, #21

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@15593 29f149b2-0c63-11e1-8f5c-a347f6a9acd0
adapting the PATH and SUMO_HOME in the installer, refs #3

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@15594 29f149b2-0c63-11e1-8f5c-a347f6a9acd0