adding axes sharing to displays of related images

for better interaction

sharing achieved by setting sharex and sharey, and
setting the axes 'adjustable' parameter to 'box-forced'

doc/examples/plot_peak_local_max.py

@@ -25,7 +25,7 @@ image_max = ndi.maximum_filter(im, size=20, mode='constant')
 coordinates = peak_local_max(im, min_distance=20)
 
 # display results
-fig, ax = plt.subplots(1, 3, figsize=(8, 3))
+fig, ax = plt.subplots(1, 3, figsize=(8, 3), sharex=True, sharey=True, subplot_kw={'adjustable':'box-forced'})
 ax1, ax2, ax3 = ax.ravel()
 ax1.imshow(im, cmap=plt.cm.gray)
 ax1.axis('off')