new embedding_in_wx3 example

OK, I discovered a rather easy demonstration of what looks

  > to be a OK, (possibly the same) bug (adding 'ylim' to the
  > image_origin demo):

    from matplotlib.matlab import *
    x = arange(100.0); x.shape = 10,10

    title('blue should be up')
    imshow(x, origin='upper', interpolation='nearest')

    title('blue should be down')
    imshow(x, origin='lower', interpolation='nearest')


I agree it looks like a bug. Just to make sure we are on the same
page: what do you thing the correct behavior should be here? Do you
think subplot (211) is correct?

The question is: how should image origin interact with the axes
ylimits? In this example, should both images fill the space from 0-10
on the y axes, regardless of the ylimit setting? In the origin upper
case, should the blue strip be at 10 and the red strip at zero? In
the origin lower case, should the blue be at zero and the red at 10?

Inquiring minds want to know.