C++ standard states that all class member variables are initialized in
the order they are declared in the class. Thus, it is considered good
C++ style to have their initialization listing in the constructor to
match the actual order they are initialized. The compiler could give a
warning otherwise.
While I am at it, rename the member variables to be more aligned with
VTK-m coding style (i.e. start with capital letter and be descriptive).
ee73ab96a8