Implement xacro support

[bi3ri]

Hello,

I wanted to follow this tutorial, but I used xacro to describe my project and up until now only urdf is supported. Not sure, but I think xacro is/should be the standard by now, which excludes most users.

Cheers,
Johannes

[Levi-Armstrong]

Yea, that will not be hard to integrate for the snap package. Tesseract is ROS agnostic so xacros are not used internally and expects everything to be converted to urdf.