ENH: Update ShapePopulationViewer extension

This updates the ShapePopulationViewer extension to
f9e2c1d832096e7d17dc4e8ff9bce6f91f2eebb6.
Merge pull request #696 from fbudin69500/update-ShapePopulationViewer-master

ENH: Update ShapePopulationViewer extension
ENH: Add MyExtension extension

Description:
This is an example of a simple extension. Yeahh

Contributors:
Jc (Kitware)