There were a couple of places where the configure scripts did not add
either includes to VTKm_INCLUDE_DIRS or libraries to VTKm_LIBRARIES.

The biggest offender was when the examples used find_package to load the
VTK-m configuration it needed. find_package cleared out the includes and
libraries, but it did not clear out the VTKm_<COMPONENT>_FOUND
variables. Normally, these variables would not be set before
find_package is called, but in this case the examples were called after
some partial configuration. I got around this issue by clearing out all
the *_FOUND variables in VTKmConfig.cmake.