Test failures on Python 3.2 / IPython 0.13.1 / NumPy 1.6.2

The failure in `test_setitem` ends with:

            # single row
            bg[2] = colors
            for block in bg[2]:
    >           assert block.rgb == colors
    E           assert (1, 2, 3) == (21, 22, 23)
    E             At index 0 diff: 1 != 21

    ipythonblocks/test/test_blockgrid.py:284: AssertionError

The failure in `test_setitem_lower_left_slice` ends with:

            for pix in ll._grid[0]:
    >           assert pix.red == 201
    E           assert 7 == 201
    E            +  where 7 = <ipythonblocks.ipythonblocks.Pixel object at 0x2d60ad0>.red

    ipythonblocks/test/test_imagegrid.py:113: AssertionError

These both seem to have to do with some sort of slicing issue, but I haven't tracked down the particulars yet.  Python 2.7.3 (with the same IPython and NumPy) does pass the test suite.