Render only valid data in charts

This fixes a bug in which the charts would render invalid
points/data. This updates the charting/ploting classes to make
use of the vtkValidPointMask array and only render valid data.

Change-Id: Ic0ab56dc5422b73253a6ef56d1f32e122a002335
Merge topic '14098-skip-invalid-points' into next

988412c Render only valid data in charts