Adding a package urg_description

[vincentrou]

Adding a new package urg_description along urg_node, where to store urdf and meshes for visualization and simulation.

I have put meshes and urdf for 04lx and utm30lx here : https://github.com/vincentrou/urg_node/tree/sensor_description

A discussion about good practice about where to store sensor description is here : https://groups.google.com/forum/#!topic/ros-sig-drivers/UDEdIMiL0MU

[NikolausDemmel]

+1

[doisyg]

+1

[YoshuaNava]

+1

[130s]

Another related thread where I also linked to an example I recently made using openni driver (which even includes a simple unit test).