Added a namespace to the sensor model to be used in both the darwin and the bioloid robots.

See merge request !1

Added a module to simulate the AVR EEPROM. Needed for the new Dynamixel slave interface of the firmware.

Set real time to the simulation.
Changed the expansion board ID in the Dexter simulation files.

Added a materials xacro file for the RVIZ.

Changed the reference frames of the obstacles environment and QR codes to make them coincide with the real ones.

Added the dyn_master_start_read_table() and dyn_master_wait_read_table() functions needed by the new expansion board loop function.

Changed the background color of the tags from grey to white. This imporves the detection rate of the algorithms.

Changed the angle range and motion limits of the emmulated dynamixel servos to coincide with the real ones.

modified ceabot_motion files, now ceabot_motions=ceabot_motions_real works for real robot, ceabot_motions_sim works in simulated environment

Solved a bug in the one time user time function. It now works as expected instead of always being active.

Used the low resolution model for the basic Bioloid CEABOT robot.

The obstacles can now be moved by the robot.

Integrated the use of the pan&tilt unit in all CEABOT launch files.
Added the urdf, xacro and gazebo files for the IDS XS camera.
TEmporal chnages to try to redirect the printf output to a virtual serial device.

Inverted the output levels of the GPIO to match the data from the real feet sensors.

Substituted the servo PID's controllers for compliance controllers, more similar to the real servos.
The walk timeout is updated each time a new cmd_vel is received, whatever the current state.

Reduced the friction on the feet.