interpolate in jpynb

interpolation has changed

```
from scipy.interpolate import interp1d
...
time_smooth = np.linspace(time_sm.min(), time_sm.max(), 300)
feedback_smooth = interp1d(time_list, feedback_list, kind='quadratic')
...
plt.plot(time_list, setpoint_list)
plt.plot(time_smooth, feedback_smooth(time_smooth), ':')
```