Added sections to gallery of examples

Modified travis_script.sh to account for the new structure of the gallery

Added README.txt files in directories of gallery examples

Fixed references to gallery images in user guide pages

Fixed broken links

doc/examples/features_detection/plot_censure.py

@@ -0,0 +1,43 @@
+"""
+========================
+CENSURE feature detector
+========================
+
+The CENSURE feature detector is a scale-invariant center-surround detector
+(CENSURE) that claims to outperform other detectors and is capable of real-time
+implementation.
+
+"""
+from skimage import data
+from skimage import transform as tf
+from skimage.feature import CENSURE
+from skimage.color import rgb2gray
+import matplotlib.pyplot as plt
+
+
+img1 = rgb2gray(data.astronaut())
+tform = tf.AffineTransform(scale=(1.5, 1.5), rotation=0.5,
+                           translation=(150, -200))
+img2 = tf.warp(img1, tform)
+
+detector = CENSURE()
+
+fig, ax = plt.subplots(nrows=1, ncols=2)
+
+plt.gray()
+
+detector.detect(img1)
+
+ax[0].imshow(img1)
+ax[0].axis('off')
+ax[0].scatter(detector.keypoints[:, 1], detector.keypoints[:, 0],
+              2 ** detector.scales, facecolors='none', edgecolors='r')
+
+detector.detect(img2)
+
+ax[1].imshow(img2)
+ax[1].axis('off')
+ax[1].scatter(detector.keypoints[:, 1], detector.keypoints[:, 0],
+              2 ** detector.scales, facecolors='none', edgecolors='r')
+
+plt.show()