Implemented ForceTorque Sensor and tested

The sensor will provide data for left and right leg only, in the same way as the real robot.
Add configuration files for force torque sensors on legs
Improved the interface between yarp and robotran for the update function, now it uses a pure virtual interface to generalize more.
Pushing some function I probably got while moving plugins from OffRoad model
to CoMan (?), and now they are required for compilation.

Hope this does not causes conflicts or make things wrong