- Exception classes cannot be exported due to MSVC's design decisions.
  See http://stackoverflow.com/questions/24511376. We must leave these
  classes as header only and silence the warnings.
- TransferResource in BufferState.h must remain a header-only class since
  there is no vtkm_interop library to compile the class into.
- The VTKDataSetReader hierarchy must similarly remain header-only since
  there is no vtkm_io library.
- The OptionParser Action classes are part of a header-only utility and
  cannot be easily compiled into a library.
-