Fix VTK-m compile errors
The test directory for the VTK-m accelerator directory was failing on some platforms because the test code was directly including some VTK-m header files, and the VTKm_INCLUDE_DIRS was not set correctly for the CXX testing directory.
The solution in this topic branch is to remove all direct dependency on VTK-m when using the vtkAcceleratorsVTKm library. There is no good reason not to completely encapsulate the library, which should simplify code using it.
Edited by Kenneth Moreland