Major refactor of InteractiveSegmentTubes

Big refactoring of InteractiveSegmentTubes to allow the user to click his
way through the image while the segment tubes cli is automatically ran.
Also separate the classes in different files to make coding and reading
easier.
Bump TubeTK to get the interactive segment tubes fixes/improvements
Merge new result to the current output node

This allow to segment different vessels at different times and still have
them all under the same spatial object
Add a show/hide seeds text option