Merge pull request #782 from sciunto/pep8

PEP8 + docstrings

doc/examples/plot_join_segmentations.py

@@ -60,4 +60,3 @@ for ax in axes:
     ax.axis('off')
 plt.subplots_adjust(hspace=0.01, wspace=0.01, top=1, bottom=0, left=0, right=1)
 plt.show()
-

doc/examples/plot_marching_cubes.py

@@ -22,7 +22,6 @@ voxel spacing is not equal for every spatial dimension, through use of the
 """
 import numpy as np
 import matplotlib.pyplot as plt
-from mpl_toolkits.mplot3d import Axes3D
 from mpl_toolkits.mplot3d.art3d import Poly3DCollection
 
 from skimage import measure