[WIP] segmentation api

[Hoda1394]

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Summary

Checklist

• I have added tests to cover my changes
• I have updated documentation (if necessary)

Acknowledgment

• I acknowledge that this contribution will be available under the Apache 2 license.

[Hoda1394]

I have some confusion about the object itself.

1. what variables we should consider for instantiating the estimator object? (here the segmentation case)
2. it seems that predict also should be a function rather than a method like the evaluate function?