add commented dot graph properties
add commented dot graph properties

would be useful to expose setting these when calling graph2dot functions
necozay/tulip-control,tulip-control/tulip-control,tulip-control/tulip-control,tulip-control/tulip-control,tulip-control/tulip-control,necozay/tulip-control,necozay/tulip-control,necozay/tulip-control,necozay/tulip-control