Image tutorial notebook edit

Make the Image tutorial more friendly to people using the IPython notebook to follow along (avoid use of set_xxx functions, use arguments to imshow instead.)

Also:
- use scipy.ndimage for image resizing in last example (interpolation)
- minor grammar fixes
- add notes about keeping plt commands in one cell so that effects are shown.
It has been too long, I don't remember I'm afraid.  I think my line of thought was simplicity, plus it might have had something to do with some aliasing that caused bins to merge and look sloppy when the image was too small.  Vague recollection, though, take with a grain of salt.  If you think the styling adds to the tutorial, it should absolutely stay in.