Loop: reordered loop_box arguments to be more standard

[SamuelCupp]

loop_box and loop_box_device both had the function argument 'f' first, while all other functions have this argument last. This changes them to match.

[eschnett]

@SamuelCupp PR #174 (just merged) should include your changes. Can you confirm?

[SamuelCupp]

It looks like it contains all the changes in the code that is compiled. However, loop_box_boundary in loop.hxx was not reordered to have the f argument last. Similarly, loop_box_boundary_device in loop.hxx removed the f argument from the front but didn't add it to the end of the argument list. These are both currently surrounded by #if 0 logic, so they aren't compiled.

[eschnett]

Applied in #177.