Change the VTKM_CONT_EXPORT to VTKM_CONT. (Likewise for EXEC and
EXEC_CONT.) Remove the inline from these macros so that they can be
applied to everything, including implementations in a library.
Because inline is not declared in these modifies, you have to add the
keyword to functions and methods where the implementation is not inlined
in the class.
First, be more explicit when we mean a range of values in a field or a
spacial bounds. Use the Range and Bounds structs in Field and
CoordinateSystem to make all of this more clear (and reduce a bit of
code as well).
