Add script to visualize VTK PolyData.

This utility script can be used to create screenshots of examples meshes.  It
can output to screen, PNG, or WebGL HTML.  Pressing the "c" from the
interative view will output the command line flags to restore the current Camera
settings on subsequent runs.

Change-Id: I5d4eddb4efe7000ecbe7e2cbae645f9e9a436979
Merge "Add script to visualize VTK PolyData."