Revert "Merge pull request #2 from kiyo-masui/axis_order"

This reverts commit 5c9e50695413e71dde901dcd4491907b9d8ee993, reversing
changes made to 208ca7b29b97fa75c8846b80c2401470bc6f37ac.

After discussing with Jon, we want old axis ordering with frequency as
the fastest varying.