Include Xacro support in the drag and drop example

[gkjohnson]

From here:

https://github.com/gkjohnson/xacro-parser

[yvanblanchard]

Hello,
Does it mean that this capability (drag and drop a xacro file) is an on-going feature, and thus not available yet from live demo web page yet ?

[gkjohnson]

That's correct - xacro is not supported in the in the drag and drop demo page at the moment. However there are instructions in the README on how to use the xacro parser with the urdf loader in your own project, though.