Make virtual sensor a separated package. In kobuki-x by now; to yujin_ocs when generic enough
Include a wall virtual sensor
Move the common code to a new package: math_toolkit. This package will be moved to yocs in the near future, as soon as it gets stable enough. It's intended to contain common use math functions and tf-related conversions
Move virtual_sensor geometry functions to math_tolkit
Add BSD license file (make the proper link on the code when moved to yocs