Added missing python_view.py file

Change-Id: I3be09bad30f0d4239170ce85916dbf2301a5cd44
Added check for null instance of vtkMatplotlibUtilities

This prevents a crash if matplotlib is not available on the system.

Change-Id: Ie371c3d6a44addd09f86fbd9323cc99221e0454b
Matplotlib must now be enabled to expose the Python View

Tests are now disabled if matplotlib is not available at build time.

Change-Id: Id0298858467851a03504cdab2a701d46423a2ab4
Merge topic 'PythonView' into next

fe429d9 Matplotlib must now be enabled to expose the Python View
53e15d0 Added check for null instance of vtkMatplotlibUtilities
a1a8d78 Added missing python_view.py file