Stop using deprecated scipy.ndimage namespaces

[nicolascedilnik]

With recent versions of scipy, a lot of warnings are raised:

DeprecationWarning: Please use label from the scipy.ndimage namespace, the scipy.ndimage.measurements namespace is deprecated.

DeprecationWarning: Please use grey_dilation from the scipy.ndimage namespace, the scipy.ndimage.morphology namespace is deprecated.
from scipy.ndimage.morphology import grey_dilation

Please use gaussian_filter from the scipy.ndimage namespace, the scipy.ndimage.filters namespace is deprecated.

This PR removes them

[nicolascedilnik]

No love for future-proofedness?