Add the base of the PolygonEditionHelper
This provides a generic way to edit list of mask polygons.
Merge branch 'master' into polygon-edition-helper
Can now change the selected polygon/point from the editor
Make some adjustments in the PolygonEditionHelper
Merge branch 'master' into polygon-edition-helper
Merge branch 'master' into polygon-edition-helper
Fix polygon include in PolygonEditionHelper
Add documentation to PolygonEditionHelper
Merge pull request #25 from victorlevasseur/polygon-edition-helper

Added PolygonEditionHelper to make polygon edition easier and adaptable to other object editors.