Improve descriptions of jointTorqueCtrl parameters
Add check on friction parameter std dev

- if the standard deviation of the friction parameters of the joints
under excitation gets below threshold, then stop the excitation process.
- increse print period from 1 to 2 seconds
- increase max PWM from 300 to 400
- increase max position integral from 30 to 50
- inprove configuration files
Add save of all module parameters on file

When the identification module receive the "save" rpc command it saves
not only the current parameter estimations, but also all the module
parameters (in another text file). This could be useful to check the
estimation covariances after the identification has finished.