* Support a REQUIRED flag that only gives an error if that flag is given.
* Move common configuration required for all devices (such as boost) to a
special device named Base.
* Make CUDA always capitalized to be consistent with the other CMake
variables.
* Rather than call include_directories, set a variable named
VTKm_INCLUDE_DIRS. This is consistent with how most CMake packages work.
* Make a CMake variable named VTKm_LIBRARIES containing all the
libraries the configured devices need.
* Automatically configure supported devices when loading the VTK-m
package in CMake.
Porting the dax device adapter over to vtkm. Unlike the dax version, doesn't
use the thrust::device_vector, but instead uses thrust::system calls so that
we can support multiple thrust based backends.
Also this has Texture Memory support for input array handles. Some more work
will need to be done to ArrayHandle so that everything works when using an
ArrayHandle inplace with texture memory bindings.
