Changed the way the detected servos are stored in memory for performance...

Changed the way the detected servos are stored in memory for performance issues. The Id coincides with the vector position.
Added a new attribute to the servo info structure to hold the motion module associated to the servo (ACTION or JOINTS for now).
Added support to detect and handle the simulated dynamixel servos.
Removed the dynamixel master initialization from the motion manager.
Added a module to implement a pan&tilt unit.