1. Change set_property(...) to target_* commands
2. Remove explcit adding of CMAKE_CXX_FLAGS_WARN_EXTRA as compile option
3. Add /bigobj option to VTKm_COMPILE_OPTIONS under MSVC
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.
The examples are now written so they can be copied out of the vtk-m
source and still build properly. This will help new users / developers
learn how to build projects that use VTK-m.
This is needed as it allows the policies specified in the root of
vtk-m to propagate properly to the examples. When CMake
sees a cmake_minimum_required command it resets all policy flags.
