Adding ImplicitAnnulusWidget

src/Cxx.md

src/Cxx/GeometricObjects/ConesOnSphere.cxx

src/Cxx/GeometricObjects/GoldenBallSource.cxx

src/Cxx/GeometricObjects/SphereSource.cxx

src/Cxx/Widgets/ImplicitAnnulusWidget.cxx

src/PythonicAPI.md

src/PythonicAPI/GeometricObjects/ConesOnSphere.py

src/PythonicAPI/GeometricObjects/GoldenBallSource.py

src/PythonicAPI/GeometricObjects/SphereSource.py

src/PythonicAPI/Widgets/ImplicitAnnulusWidget.py

src/PythonicAPI/Widgets/ImplicitPlaneWidget2.py

...esting/Baseline/Cxx/Widgets/TestImplicitAnnulusWidget.png

...aseline/PythonicAPI/Widgets/TestImplicitAnnulusWidget.png