impedance control consistency

[randaz81]

Write a test which performs the following actions:

PART1:

• set a small pre-defined impedance value (e.g. stiffness 0.2 damping 0.2) on all joints of the robot part.
• read back the impedance from all the joints. Retrieved value should not differ more than (0.05 0.05) from the original command.
• Repeat using a large pre-defined impedance value (e.g. stiffness 10.0 damping 10.0).
• Threshold and test values should be stored in a ini file.

PART2:

• call function yarp::dev::IImpedanceControl::getCurrentImpedanceLimit (int j,double * min_stiff,double * max_stiff,double * min_damp,double * max_damp ))
• repeat the tests using the max/min values obtained by getCurrentImpedanceLimit() in place of the predefined values used in PART1.