blendertools: added emission and ambient color to export
blendertools: changed creation of joint names
blendertools: changed sensor material to be easier locatable
blendertools: correct urdf export of optional transparency
blendertools: getImmediateChildren now supports multiple types
blendertools: added utility function for outer product
Merge branch 'master' of github.com:rock-simulation/mars
implemented experimental RotatingRaySensor