Added modules that create a numpy type interface.

Added modules that wrap VTK datasets and arrays with a numpy
type interface to make it easy to calculate derived quantities
in Python.

Change-Id: I35355eb54c4f7a89176fe22cbf4a7a179e2a9bd4
Merge topic 'numpy-interface-3' into master

79a80ae6 Added modules that create a numpy type interface.