Fix inconsistencies in examples and many more improvements

doc/examples/plot_watershed.py

@@ -24,13 +24,14 @@ See Wikipedia_ for more details on the algorithm.
 .. _Wikipedia: http://en.wikipedia.org/wiki/Watershed_(image_processing)
 
 """
-
 import numpy as np
-
 import matplotlib.pyplot as plt
+from scipy import ndimage
+
 from skimage.morphology import watershed
 from skimage.feature import peak_local_max
 
+
 # Generate an initial image with two overlapping circles
 x, y = np.indices((80, 80))
 x1, y1, x2, y2 = 28, 28, 44, 52
@@ -41,7 +42,6 @@ image = np.logical_or(mask_circle1, mask_circle2)
 
 # Now we want to separate the two objects in image
 # Generate the markers as local maxima of the distance to the background
-from scipy import ndimage
 distance = ndimage.distance_transform_edt(image)
 local_maxi = peak_local_max(distance, indices=False, footprint=np.ones((3, 3)),
                             labels=image)