Render trailing good points in line/point plots

This fixes a bug in which the trailing good points in a
data set would be skipped.

Change-Id: I5686c1b1c5ec3e77d29cd63327bdbd98702472bc
Fix bounds calculation for vtkPlotPoints with bad points

This fixes an issue when calculating the bounds of good points
in the vtkPlotPoints class.

Change-Id: I0ce811100057ddbfd52ba3827e2e4aef92a89927