Merged requested to merge kmorel/vtk-m:data-license into master
The VTK-m source comes distributed with several data files used for regression testing. Some of these are generated specifically by VTK-m developers and are released as part of the VTK-m license, but some come from external sources. For those that come from external sources, we have clarified the license and attribution of those files. In particular, the following files originate from external sources.