ZFP Added to VTK

Just trying to keep a log here.  I added the zfp .5 to VTK 7 to allow lossy compression to 3D datasets.  It works, but you do have to specify the extent of the data to the compressor separately.  I may be able to avoid this in the future, but this is what you get with object oriented design sometimes.  Check it out here: https://gitlab.kitware.com/stephenshamilton/vtk/tree/zfp