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.
The word surface is more often used for something like a polygonal mesh,
so this name is quite confusing. Canvas is consistent with a
conventional name in GUI widget APIs.
The rendering classes do not actually manage windows, and window was not
descriptive of what this class was doing. We decided that the class was
mostly analogous to what we call a "view" in ParaView.
