ENH: Add test for ParallelCoordinatesView

vtkParallelCoordinatesView was not tested. The lack of a test
resulted in low coverage for vtkParallelCoordinatesView,
vtkParallelCoordinatesRepresentation and SCurveSpline.

This patch also repairs a memory leak in
ParallelCoordinatesRepresentation that was uncovered when the test was
added.

Also, since vtkSCurveSpline is only used in
vtkParallelCoordinatesRepresentation and vtkSCurveSpline did not have a unit
test, this path moves vtkSCurveSpline is moved into Views/Infovis.

NOTE: vtkParallelCoordinatesView has a lot of interactive content. To
improve the coverage, future tests must exercise the interactive parts
of this class. This patch is a minimal effort at improving the
coverage.

Change-Id: I1dfe93ecb1db85edfc5a887c4576c6274e8284ea
Merge topic 'Coverage_ParallelCoordinatesView' into master

7a9edc68 ENH: Add test for ParallelCoordinatesView