- Introduces a xacro file that loads the Gazebo control plugin.
- This enables to control the gripper in Gazebo, e.g. with the
"Robotiq3FGripperSimpleController.py".
- Removes the "side" parameter and replaces it with an optional
"prefix" parameter that allows to use arbitrary names.

Fix deprecated xacro syntax without namespace prefix

RViz plugin

Translated French comments to English

Add pre-release builds and update README

readme: added license badges

fix mimic joint limits

Addition of URDF for the 85mm stroke C3 gripper and FT300 sensor

- FT300 - force/torque sensor mesh files for visualization and collision
- FT300 mounting plate
- Macro function with documentation on how to use it
- Launch file allowing the easy visualization and testing of sensor macro function. 

replace control msgs with robotiq_3f_gripper_articulated_msgs

Mesh colour

- Modification of `package.xml`s
- Modification of `.launch` files
- Small changes in URDFs

Fix gazebo launch