Added macros just like vtkSetMacro/vtkGetMacro that work with 'enum class'

Since C++11 'enum class' does not implicitly convert to integers, the existing vtkSetMacro/vtkGetMacro can't work with them.

Added two new macros vtkSetEnumMacro/vtkGetEnumMacro that do work.

They are not yet used anywhere.