remove io.py

conflicting name hinders installation
Extend interpolation to last column.

commit 3168cc68b283e55b8a23c3b8a915cb5aa06e62c8
Author: Yu Feng <yfeng1@coma.hpc1.cs.cmu.edu>
Date:   Thu Jul 18 18:53:28 2013 -0400

    Extend interpolation to last column.

    Previously, the interpolation skips last column, for example,

    a = [1, 1]
    x = [0, 0.5, 1, 1.5]
    map_coordinate(a, (x, ), mode='constant')

    gives 1 1 1 0.

    After this fix, it gives 1 1 1 1. (see test case), which in my opion
    makes more sense; this will also potentially allow us to get rid
    of a few shape hacks in zoom and shift.

    This also fix 'wrap', making its output N periodic,
    compatible with numpy's definition of 'wrap'. Previously it was
    broken (N - 1) periodic, with the first element handled inconsistently.

    The boundary handling is enforced after the
    spline interpolation is applied, even though in the code
    appears before calling the splev.

    Note that the spline filter assumes a 'reflect' boundary.
    see, the definition of boundary in
    http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.68.6734&rep=rep1&type=pdf
    (last two pages)

    The only boundary that is consistent with the spline is 'reflect'.

    All other boundaries shall be used with caution.