contains() tests broken

Hi,

In my attempt to get scroll wheel zooming working for this release I added
support for the scroll wheel to TkAgg, and added support for draw_idle to
the wx backend.

I'm attaching the wheel zoom demonstration code. This is standalone code
which is not yet ready to go into backend_bases. It only supports linear
and log axes. Using transform magic would be better here. Also, colormap
zooming is hacked (I don't know how to determine if the axes contain a
colorbar, and what the corresponding mappable is, so I put a list of
colorbars in the figure).

In the process of developing this code I noticed that a lot of the contains
tests are broken by the new transforms. Try attaching onHilite to the
motion notify event on any canvas --- objects should turn light blue as you
hover over them.

E.g.,

  from pylab import plot, gcf, show
  plot([1,2,3],[1,5,2])
  cvs = gcf().canvas
  cvs.mpl_connect('motion_notify_event',cvs.onHilite)
  show()

I can fixes the axis hit test. I'm not sure how many other problems there
are, but I'm pretty sure I won't get to them all before next Tuesday.

   - Paul

zoomwheel.py (3.58 KB)