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/transform/plot_edge_modes.py

@@ -0,0 +1,37 @@
+"""
+=========================
+Interpolation: Edge Modes
+=========================
+
+This example illustrates the different edge modes available during
+interpolation in routines such as `skimage.transform.rescale` and
+`skimage.transform.resize`.
+"""
+from skimage._shared.interpolation import extend_image
+import skimage.data
+import matplotlib.pyplot as plt
+import numpy as np
+
+img = np.zeros((16, 16))
+img[:8, :8] += 1
+img[:4, :4] += 1
+img[:2, :2] += 1
+img[:1, :1] += 2
+img[8, 8] = 4
+
+modes = ['constant', 'edge', 'wrap', 'reflect', 'symmetric']
+fig, axes = plt.subplots(1, 5, figsize=(15, 5))
+for n, mode in enumerate(modes):
+    img_extended = extend_image(img, pad=img.shape[0], mode=mode)
+    axes[n].imshow(img_extended, cmap=plt.cm.gray, interpolation='nearest')
+    axes[n].plot([15.5, 15.5], [15.5, 31.5], 'y--', linewidth=0.5)
+    axes[n].plot([31.5, 31.5], [15.5, 31.5], 'y--', linewidth=0.5)
+    axes[n].plot([15.5, 31.5], [15.5, 15.5], 'y--', linewidth=0.5)
+    axes[n].plot([15.5, 31.5], [31.5, 31.5], 'y--', linewidth=0.5)
+    axes[n].set_axis_off()
+    axes[n].set_aspect('equal')
+    axes[n].set_title(mode)
+
+plt.tight_layout()
+
+plt.show()