add KHI CAD Data Disclaimer to README

[matsui-hiro]

LIcense for ** _ description is BSD.
But, there is a disclaimer of KHI CAD Data.
Therefore, URDF STL files need to be compliant.
I added it to the README.

[gavanderhoorn]

The license tag in package manifests can occur multiple times in a manifest (see REP 140).

Perhaps adding a second license tag for this would be more visible (contents of license tags is shown on the ROS wiki pages for instance).

Example:

  <license>KHI CAD license (mesh data, see readme)</license>

or if using format 3 (REP 149), you could consider placing the license text in a separate file and refer to it from the license tag (path is relative to the package.xml):

  <license file="khi_cad_license.txt">KHI CAD license (mesh data)</license>

[matsui-hiro]

@gavanderhoorn:Thank you for your suggestion !

I adopt the upper idea.

  <license>KHI CAD license (mesh data, see readme)</license>

This KHI licese tag will be added to package.xml of *** _ description .