Dependency problem in Kinetic

[Raziel90]

Hello,

I wanted to inform the authors that the version of urdfdom-py available for kinetic has problems with default values in the urdf files.
For example if the urdf has <origin xyz="0 0 0"> the rpy value of such joint will be set to None instead of [0,0,0] like newer versions would do. I think this situation can be easily managed in the urdf_load function.
This is the only problem I have actually encountered in testing the package on ros kinetic so far.