Improving jacobian derivative to consider base

[maripaf]

Today the function that calculates the jacobian time derivative does not consider the transformation of base and end-effector of the robot (set_base and set_effector).
It would be nice to have a function that already considers these transformations.

[juanjqo]

Hi @bvadorno,

This issue was fixed in #75.

Best regards,

Juancho