Squashed commits:

* add roslaunch tests
* add missed dependencies
* Do not install roslaunch tests.

Squashed commits:

* Fix overlapping properties between robot definitions

   Uploading a different UR definition used to break the previous definition files by overwriting their link lengths. This commit makes the property names for each robot unique so they are independent of the other robot models.

* Move robot-specific parameters inside macro

   This is the cleaner solution for what the previous commit was meant to solve

Merged commits:

* missed python module definition and setup.py script
* clean the __init__ file

Using the 'doc' attribute on 'arg' elements.

readme: add badge and dev job link.

Fix meshes

Gazebo tag self collide

ur_moveit_plugin: fix compile error with GCC6

related to issue 'Improve meshes shading #233'. Visual meshes smoothed with 'split edge' function in blender.

Added run_depend for xacro

add doc strings to all launch file args.

driver: don't use deprecated robot_state binary.

Homogenize xacro macro arguments.

Remove UR3 ROS Control Hardware Interface warning

Joint limits for the limited version could be set using arguments for the UR10
but not for the UR3 and UR5. Same lower and upper limit arguments are added to
the UR3 and UR5 xacro macros.

Updated urdf::ModelInterface pointer type for ROS Lunar