Urdf shapes fix

Now you can draw other shapes.

Example, try:
roslaunch urdf_tutorial display.launch model:=urdf/05-visual.urdf
rosrun tf2_web_republisher tf2_web_republisher
roslaunch rosbridge_server rosbridge_websocket.launch

and open on browser: examples/urdf.html
Merge pull request #60 from Vegekou/patch-1

Urdf shapes fix