Hi Juan,

I made the changes to add SLIC-zero but the code has become a bit messy and redundant... I think it's not ready for a pull request yet but I would welcome some feedback :)

https://github.com/romaniukm/scikit-image/tree/slico

I also updated the plot_segmentations.py example to add SLIC-zero to the comparison. It's available here:

https://gist.github.com/romaniukm/7679402

Michal