Fix __str__() to have correct alignment

Fix __str__() to have correct alignment in `DynParams` and `GeoParams`
classes.
Update corresponding __repr__() accordingly.
Add methods to update geometric and dynamic params

Add methods to update the geometric and dynamic parameters of the robot.
The method is called update_params().
Add put_val() method to communicate with the user interface. The
put_val() method updates the parameters by calling the update_params()
method.
NOTE: Currently only geometric and dynamic parameters can be updated.