Checking and updating python files and images

src/Python/Graphs/NOVCAGraph.py

src/Python/IO/3DSImporter.py

src/Python/IO/ReadSLC.py

src/Python/IO/ReadSTL.py

src/Python/IO/ReadUnstructuredGrid.py

src/Python/IO/ReadVTP.py

src/Python/IO/WritePLY.py

src/Python/IO/WriteSTL.py

src/Python/IO/WriteTriangleToFile.py

src/Python/ImplicitFunctions/Sphere.py

src/Python/InfoVis/ParallelCoordinatesExtraction.md

src/Python/InfoVis/ParallelCoordinatesExtraction.py

src/Python/InfoVis/ParallelCoordinatesView.md

src/Python/InfoVis/ParallelCoordinatesView.py

src/Python/InfoVis/SelectedGraphIDs.py

src/Python/Interaction/CallBack.py

src/Python/Interaction/HighlightPickedActor.md

src/Python/Interaction/HighlightPickedActor.py

src/Python/Interaction/MouseEvents.py

src/Python/Interaction/MouseEventsObserver.py