Examples in docs

[pchlap]

• [x] Visualisation (already exists)
• [ ] Image registration (Rob)
• [x] Atlas based segmentation (Phil)
• [ ] Synthetic deformation (fast example) (Rob)
• [x] Contour comparison metrics (Phil)
• [x] DVH analysis (already exists)
• [x] Bronchus segmentation page (maybe) (Phil)
• [ ] Update README with images from examples and link to examples (both)

[rnfinnegan]

Could use dummy data (cylinder, spheres) for some of these