add tiff heightmap, refs #1495

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@17331 29f149b2-0c63-11e1-8f5c-a347f6a9acd0
adding heightmap test, adapting help output, refs #21, #1495

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@17332 29f149b2-0c63-11e1-8f5c-a347f6a9acd0
Merge branch 'master' into planet