Make the random colormap based on CIELAB by default
Document imshow_rand
Add docs for common functions
Import itertools module, not just a function
Overhaul 3D segmentation display
Add doc
Add docs to plot_vi_breakdown_panel
Add docs for plot_vi_breakdown; remove plot_vi_parts
Improve doc for show_merge_3D
Add more control over plotting in viz.py
Add more docstrings to viz.py functions
Remove unused viz.py functions
Merge pull request #13 from jni/improviz

Various improvements to the viz module