Will Schroeder authored Feb 15, 2015 and Bill Lorensen committed Mar 13, 2015

vtkCheckerboardSplatter is a much faster implementation of
vtkGaussianSplatter. It also makes use of multithreading through
vtkSMPTools. vtkGaussianSplatter was also sped up by using these
same multithreading tools.

Change-Id: If8b987231b973e7005bba563af1c6933d61f0bb1